X-Git-Url: http://git.imager.perl.org/imager.git/blobdiff_plain/5715f7c346843625ebcd21c2d2d57edd6473cce0..a87997b2f901c06ea67e73d89558aa376f64019b:/image.c

diff --git a/image.c b/image.c
index dfd6f1cf..03dc6e2c 100644
--- a/image.c
+++ b/image.c
@@ -1,3 +1,5 @@
+#define IMAGER_NO_CONTEXT
+
 #include "imager.h"
 #include "imageri.h"
 
@@ -12,7 +14,7 @@ image.c - implements most of the basic functions of Imager and much of the rest
   i_color *c;
   c = i_color_new(red, green, blue, alpha);
   ICL_DESTROY(c);
-  i = i_img_new();
+  i = i_img_8_new();
   i_img_destroy(i);
   // and much more
 
@@ -30,6 +32,8 @@ Some of these functions are internal.
 =cut
 */
 
+im_context_t (*im_get_context)(void) = NULL;
+
 #define XAXIS 0
 #define YAXIS 1
 #define XYAXIS 2
@@ -37,22 +41,14 @@ Some of these functions are internal.
 #define minmax(a,b,i) ( ((a>=i)?a: ( (b<=i)?b:i   )) )
 
 /* Hack around an obscure linker bug on solaris - probably due to builtin gcc thingies */
-static void fake(void) { ceil(1); }
-
-static int i_ppix_d(i_img *im, int x, int y, const i_color *val);
-static int i_gpix_d(i_img *im, int x, int y, i_color *val);
-static int i_glin_d(i_img *im, int l, int r, int y, i_color *vals);
-static int i_plin_d(i_img *im, int l, int r, int y, const i_color *vals);
-static int i_ppixf_d(i_img *im, int x, int y, const i_fcolor *val);
-static int i_gpixf_d(i_img *im, int x, int y, i_fcolor *val);
-static int i_glinf_d(i_img *im, int l, int r, int y, i_fcolor *vals);
-static int i_plinf_d(i_img *im, int l, int r, int y, const i_fcolor *vals);
-static int i_gsamp_d(i_img *im, int l, int r, int y, i_sample_t *samps, const int *chans, int chan_count);
-static int i_gsampf_d(i_img *im, int l, int r, int y, i_fsample_t *samps, const int *chans, int chan_count);
+void i_linker_bug_fake(void) { ceil(1); }
 
 /*
-=item i_img_alloc()
+=item im_img_alloc(aIMCTX)
+X<im_img_alloc API>X<i_img_alloc API>
 =category Image Implementation
+=synopsis i_img *im = im_img_alloc(aIMCTX);
+=synopsis i_img *im = i_img_alloc();
 
 Allocates a new i_img structure.
 
@@ -81,25 +77,29 @@ object.
 */
 
 i_img *
-i_img_alloc(void) {
+im_img_alloc(pIMCTX) {
   return mymalloc(sizeof(i_img));
 }
 
 /*
-=item i_img_init(C<img>)
+=item im_img_init(aIMCTX, image)
+X<im_img_init API>X<i_img_init API>
 =category Image Implementation
+=synopsis im_img_init(aIMCTX, im);
+=synopsis i_img_init(im);
 
 Imager internal initialization of images.
 
-Currently this does very little, in the future it may be used to
-support threads, or color profiles.
+See L</im_img_alloc(aIMCTX)> for more information.
 
 =cut
 */
 
 void
-i_img_init(i_img *img) {
+im_img_init(pIMCTX, i_img *img) {
   img->im_data = NULL;
+  img->context = aIMCTX;
+  im_context_refinc(aIMCTX, "img_init");
 }
 
 /* 
@@ -118,15 +118,16 @@ Return a new color object with values passed to it.
 i_color *
 ICL_new_internal(unsigned char r,unsigned char g,unsigned char b,unsigned char a) {
   i_color *cl = NULL;
+  dIMCTX;
 
-  mm_log((1,"ICL_new_internal(r %d,g %d,b %d,a %d)\n", r, g, b, a));
+  im_log((aIMCTX,1,"ICL_new_internal(r %d,g %d,b %d,a %d)\n", r, g, b, a));
 
-  if ( (cl=mymalloc(sizeof(i_color))) == NULL) i_fatal(2,"malloc() error\n");
+  if ( (cl=mymalloc(sizeof(i_color))) == NULL) im_fatal(aIMCTX, 2,"malloc() error\n");
   cl->rgba.r = r;
   cl->rgba.g = g;
   cl->rgba.b = b;
   cl->rgba.a = a;
-  mm_log((1,"(%p) <- ICL_new_internal\n",cl));
+  im_log((aIMCTX,1,"(%p) <- ICL_new_internal\n",cl));
   return cl;
 }
 
@@ -147,15 +148,16 @@ ICL_new_internal(unsigned char r,unsigned char g,unsigned char b,unsigned char a
 
 i_color *
 ICL_set_internal(i_color *cl,unsigned char r,unsigned char g,unsigned char b,unsigned char a) {
-  mm_log((1,"ICL_set_internal(cl* %p,r %d,g %d,b %d,a %d)\n",cl,r,g,b,a));
+  dIMCTX;
+  im_log((aIMCTX,1,"ICL_set_internal(cl* %p,r %d,g %d,b %d,a %d)\n",cl,r,g,b,a));
   if (cl == NULL)
     if ( (cl=mymalloc(sizeof(i_color))) == NULL)
-      i_fatal(2,"malloc() error\n");
+      im_fatal(aIMCTX, 2,"malloc() error\n");
   cl->rgba.r=r;
   cl->rgba.g=g;
   cl->rgba.b=b;
   cl->rgba.a=a;
-  mm_log((1,"(%p) <- ICL_set_internal\n",cl));
+  im_log((aIMCTX,1,"(%p) <- ICL_set_internal\n",cl));
   return cl;
 }
 
@@ -193,8 +195,9 @@ Dump color information to log - strictly for debugging.
 
 void
 ICL_info(i_color const *cl) {
-  mm_log((1,"i_color_info(cl* %p)\n",cl));
-  mm_log((1,"i_color_info: (%d,%d,%d,%d)\n",cl->rgba.r,cl->rgba.g,cl->rgba.b,cl->rgba.a));
+  dIMCTX;
+  im_log((aIMCTX, 1,"i_color_info(cl* %p)\n",cl));
+  im_log((aIMCTX, 1,"i_color_info: (%d,%d,%d,%d)\n",cl->rgba.r,cl->rgba.g,cl->rgba.b,cl->rgba.a));
 }
 
 /* 
@@ -209,7 +212,8 @@ Destroy ancillary data for Color object.
 
 void
 ICL_DESTROY(i_color *cl) {
-  mm_log((1,"ICL_DESTROY(cl* %p)\n",cl));
+  dIMCTX;
+  im_log((aIMCTX, 1,"ICL_DESTROY(cl* %p)\n",cl));
   myfree(cl);
 }
 
@@ -220,15 +224,16 @@ ICL_DESTROY(i_color *cl) {
 */
 i_fcolor *i_fcolor_new(double r, double g, double b, double a) {
   i_fcolor *cl = NULL;
+  dIMCTX;
 
-  mm_log((1,"i_fcolor_new(r %g,g %g,b %g,a %g)\n", r, g, b, a));
+  im_log((aIMCTX, 1,"i_fcolor_new(r %g,g %g,b %g,a %g)\n", r, g, b, a));
 
-  if ( (cl=mymalloc(sizeof(i_fcolor))) == NULL) i_fatal(2,"malloc() error\n");
+  if ( (cl=mymalloc(sizeof(i_fcolor))) == NULL) im_fatal(aIMCTX, 2,"malloc() error\n");
   cl->rgba.r = r;
   cl->rgba.g = g;
   cl->rgba.b = b;
   cl->rgba.a = a;
-  mm_log((1,"(%p) <- i_fcolor_new\n",cl));
+  im_log((aIMCTX, 1,"(%p) <- i_fcolor_new\n",cl));
 
   return cl;
 }
@@ -242,213 +247,6 @@ void i_fcolor_destroy(i_fcolor *cl) {
   myfree(cl);
 }
 
-/*
-=item IIM_base_8bit_direct (static)
-
-A static i_img object used to initialize direct 8-bit per sample images.
-
-=cut
-*/
-static i_img IIM_base_8bit_direct =
-{
-  0, /* channels set */
-  0, 0, 0, /* xsize, ysize, bytes */
-  ~0U, /* ch_mask */
-  i_8_bits, /* bits */
-  i_direct_type, /* type */
-  0, /* virtual */
-  NULL, /* idata */
-  { 0, 0, NULL }, /* tags */
-  NULL, /* ext_data */
-
-  i_ppix_d, /* i_f_ppix */
-  i_ppixf_d, /* i_f_ppixf */
-  i_plin_d, /* i_f_plin */
-  i_plinf_d, /* i_f_plinf */
-  i_gpix_d, /* i_f_gpix */
-  i_gpixf_d, /* i_f_gpixf */
-  i_glin_d, /* i_f_glin */
-  i_glinf_d, /* i_f_glinf */
-  i_gsamp_d, /* i_f_gsamp */
-  i_gsampf_d, /* i_f_gsampf */
-
-  NULL, /* i_f_gpal */
-  NULL, /* i_f_ppal */
-  NULL, /* i_f_addcolors */
-  NULL, /* i_f_getcolors */
-  NULL, /* i_f_colorcount */
-  NULL, /* i_f_maxcolors */
-  NULL, /* i_f_findcolor */
-  NULL, /* i_f_setcolors */
-
-  NULL, /* i_f_destroy */
-
-  i_gsamp_bits_fb,
-  NULL, /* i_f_psamp_bits */
-};
-
-/*static void set_8bit_direct(i_img *im) {
-  im->i_f_ppix = i_ppix_d;
-  im->i_f_ppixf = i_ppixf_d;
-  im->i_f_plin = i_plin_d;
-  im->i_f_plinf = i_plinf_d;
-  im->i_f_gpix = i_gpix_d;
-  im->i_f_gpixf = i_gpixf_d;
-  im->i_f_glin = i_glin_d;
-  im->i_f_glinf = i_glinf_d;
-  im->i_f_gpal = NULL;
-  im->i_f_ppal = NULL;
-  im->i_f_addcolor = NULL;
-  im->i_f_getcolor = NULL;
-  im->i_f_colorcount = NULL;
-  im->i_f_findcolor = NULL;
-  }*/
-
-/*
-=item IIM_new(x, y, ch)
-
-=item i_img_8_new(x, y, ch)
-
-=category Image creation/destruction
-
-=synopsis i_img *img = i_img_8_new(width, height, channels);
-
-Creates a new image object I<x> pixels wide, and I<y> pixels high with
-I<ch> channels.
-
-=cut
-*/
-
-
-i_img *
-IIM_new(int x,int y,int ch) {
-  i_img *im;
-  mm_log((1,"IIM_new(x %d,y %d,ch %d)\n",x,y,ch));
-
-  im=i_img_empty_ch(NULL,x,y,ch);
-  
-  mm_log((1,"(%p) <- IIM_new\n",im));
-  return im;
-}
-
-
-void
-IIM_DESTROY(i_img *im) {
-  mm_log((1,"IIM_DESTROY(im* %p)\n",im));
-  i_img_destroy(im);
-  /*   myfree(cl); */
-}
-
-/* 
-=item i_img_new()
-
-Create new image reference - notice that this isn't an object yet and
-this should be fixed asap.
-
-=cut
-*/
-
-
-i_img *
-i_img_new() {
-  i_img *im;
-  
-  mm_log((1,"i_img_struct()\n"));
-
-  im = i_img_alloc();
-  
-  *im = IIM_base_8bit_direct;
-  im->xsize=0;
-  im->ysize=0;
-  im->channels=3;
-  im->ch_mask=MAXINT;
-  im->bytes=0;
-  im->idata=NULL;
-
-  i_img_init(im);
-  
-  mm_log((1,"(%p) <- i_img_struct\n",im));
-  return im;
-}
-
-/* 
-=item i_img_empty(im, x, y)
-
-Re-new image reference (assumes 3 channels)
-
-   im - Image pointer
-   x - xsize of destination image
-   y - ysize of destination image
-
-**FIXME** what happens if a live image is passed in here?
-
-Should this just call i_img_empty_ch()?
-
-=cut
-*/
-
-i_img *
-i_img_empty(i_img *im,int x,int y) {
-  mm_log((1,"i_img_empty(*im %p, x %d, y %d)\n",im, x, y));
-  return i_img_empty_ch(im, x, y, 3);
-}
-
-/* 
-=item i_img_empty_ch(im, x, y, ch)
-
-Re-new image reference 
-
-   im - Image pointer
-   x  - xsize of destination image
-   y  - ysize of destination image
-   ch - number of channels
-
-=cut
-*/
-
-i_img *
-i_img_empty_ch(i_img *im,int x,int y,int ch) {
-  int bytes;
-
-  mm_log((1,"i_img_empty_ch(*im %p, x %d, y %d, ch %d)\n", im, x, y, ch));
-
-  if (x < 1 || y < 1) {
-    i_push_error(0, "Image sizes must be positive");
-    return NULL;
-  }
-  if (ch < 1 || ch > MAXCHANNELS) {
-    i_push_errorf(0, "channels must be between 1 and %d", MAXCHANNELS);
-    return NULL;
-  }
-  /* check this multiplication doesn't overflow */
-  bytes = x*y*ch;
-  if (bytes / y / ch != x) {
-    i_push_errorf(0, "integer overflow calculating image allocation");
-    return NULL;
-  }
-
-  if (im == NULL)
-    im = i_img_alloc();
-
-  memcpy(im, &IIM_base_8bit_direct, sizeof(i_img));
-  i_tags_new(&im->tags);
-  im->xsize    = x;
-  im->ysize    = y;
-  im->channels = ch;
-  im->ch_mask  = MAXINT;
-  im->bytes=bytes;
-  if ( (im->idata=mymalloc(im->bytes)) == NULL) 
-    i_fatal(2,"malloc() error\n"); 
-  memset(im->idata,0,(size_t)im->bytes);
-  
-  im->ext_data = NULL;
-
-  i_img_init(im);
-  
-  mm_log((1,"(%p) <- i_img_empty_ch\n",im));
-  return im;
-}
-
 /* 
 =item i_img_exorcise(im)
 
@@ -461,7 +259,8 @@ Free image data.
 
 void
 i_img_exorcise(i_img *im) {
-  mm_log((1,"i_img_exorcise(im* 0x%x)\n",im));
+  dIMCTXim(im);
+  im_log((aIMCTX,1,"i_img_exorcise(im* %p)\n",im));
   i_tags_destroy(&im->tags);
   if (im->i_f_destroy)
     (im->i_f_destroy)(im);
@@ -471,10 +270,6 @@ i_img_exorcise(i_img *im) {
   im->ysize    = 0;
   im->channels = 0;
 
-  im->i_f_ppix=i_ppix_d;
-  im->i_f_gpix=i_gpix_d;
-  im->i_f_plin=i_plin_d;
-  im->i_f_glin=i_glin_d;
   im->ext_data=NULL;
 }
 
@@ -491,9 +286,11 @@ Destroy an image object
 
 void
 i_img_destroy(i_img *im) {
-  mm_log((1,"i_img_destroy(im %p)\n",im));
+  dIMCTXim(im);
+  im_log((aIMCTX, 1,"i_img_destroy(im %p)\n",im));
   i_img_exorcise(im);
   if (im) { myfree(im); }
+  im_context_refdec(aIMCTX, "img_destroy");
 }
 
 /* 
@@ -518,11 +315,14 @@ info is an array of 4 integers with the following values:
 
 
 void
-i_img_info(i_img *im,int *info) {
-  mm_log((1,"i_img_info(im 0x%x)\n",im));
+i_img_info(i_img *im, i_img_dim *info) {
+  dIMCTXim(im);
+  im_log((aIMCTX,1,"i_img_info(im %p)\n",im));
   if (im != NULL) {
-    mm_log((1,"i_img_info: xsize=%d ysize=%d channels=%d mask=%ud\n",im->xsize,im->ysize,im->channels,im->ch_mask));
-    mm_log((1,"i_img_info: idata=0x%d\n",im->idata));
+    im_log((aIMCTX,1,"i_img_info: xsize=%" i_DF " ysize=%" i_DF " channels=%d "
+	    "mask=%ud\n",
+	    i_DFc(im->xsize), i_DFc(im->ysize), im->channels,im->ch_mask));
+    im_log((aIMCTX,1,"i_img_info: idata=%p\n",im->idata));
     info[0] = im->xsize;
     info[1] = im->ysize;
     info[2] = im->channels;
@@ -538,7 +338,7 @@ i_img_info(i_img *im,int *info) {
 /*
 =item i_img_setmask(C<im>, C<ch_mask>)
 =category Image Information
-=synopsis // only channel 0 writeable 
+=synopsis // only channel 0 writable 
 =synopsis i_img_setmask(img, 0x01);
 
 Set the image channel mask for C<im> to C<ch_mask>.
@@ -617,12 +417,15 @@ the target image.  pass NULL in C<trans> for non transparent i_colors.
 */
 
 void
-i_copyto_trans(i_img *im,i_img *src,int x1,int y1,int x2,int y2,int tx,int ty,const i_color *trans) {
+i_copyto_trans(i_img *im,i_img *src,i_img_dim x1,i_img_dim y1,i_img_dim x2,i_img_dim y2,i_img_dim tx,i_img_dim ty,const i_color *trans) {
   i_color pv;
-  int x,y,t,ttx,tty,tt,ch;
+  i_img_dim x,y,t,ttx,tty,tt;
+  int ch;
+  dIMCTXim(im);
 
-  mm_log((1,"i_copyto_trans(im* %p,src 0x%x, x1 %d, y1 %d, x2 %d, y2 %d, tx %d, ty %d, trans* 0x%x)\n",
-	  im, src, x1, y1, x2, y2, tx, ty, trans));
+  im_log((aIMCTX, 1,"i_copyto_trans(im* %p,src %p, p1(" i_DFp "), p2(" i_DFp "), "
+	  "to(" i_DFp "), trans* %p)\n",
+	  im, src, i_DFcp(x1, y1), i_DFcp(x2, y2), i_DFcp(tx, ty), trans));
   
   if (x2<x1) { t=x1; x1=x2; x2=t; }
   if (y2<y1) { t=y1; y1=y2; y2=t; }
@@ -662,10 +465,11 @@ Returns: i_img *
 
 i_img *
 i_copy(i_img *src) {
-  int y, y1, x1;
+  i_img_dim y, y1, x1;
+  dIMCTXim(src);
   i_img *im = i_sametype(src, src->xsize, src->ysize);
 
-  mm_log((1,"i_copy(src %p)\n", src));
+  im_log((aIMCTX,1,"i_copy(src %p)\n", src));
 
   if (!im)
     return NULL;
@@ -708,10 +512,11 @@ i_copy(i_img *src) {
   return im;
 }
 
+/*
 
+http://en.wikipedia.org/wiki/Lanczos_resampling
 
-
-
+*/
 
 static
 float
@@ -737,23 +542,26 @@ wither the x-axis (I<axis> == 0) or the y-axis (I<axis> == 1).
 */
 
 i_img*
-i_scaleaxis(i_img *im, float Value, int Axis) {
-  int hsize, vsize, i, j, k, l, lMax, iEnd, jEnd;
-  int LanczosWidthFactor;
-  float *l0, *l1, OldLocation;
-  int T; 
-  float t;
+i_scaleaxis(i_img *im, double Value, int Axis) {
+  i_img_dim hsize, vsize, i, j, k, l, lMax, iEnd, jEnd;
+  i_img_dim LanczosWidthFactor;
+  float *l0, *l1;
+  double OldLocation;
+  i_img_dim T; 
+  double t;
   float F, PictureValue[MAXCHANNELS];
   short psave;
   i_color val,val1,val2;
   i_img *new_img;
+  int has_alpha = i_img_has_alpha(im);
+  int color_chans = i_img_color_channels(im);
+  dIMCTXim(im);
 
   i_clear_error();
-  mm_log((1,"i_scaleaxis(im %p,Value %.2f,Axis %d)\n",im,Value,Axis));
-
+  im_log((aIMCTX, 1,"i_scaleaxis(im %p,Value %.2f,Axis %d)\n",im,Value,Axis));
 
   if (Axis == XAXIS) {
-    hsize = (int)(0.5 + im->xsize * Value);
+    hsize = (i_img_dim)(0.5 + im->xsize * Value);
     if (hsize < 1) {
       hsize = 1;
       Value = 1.0 / im->xsize;
@@ -764,7 +572,7 @@ i_scaleaxis(i_img *im, float Value, int Axis) {
     iEnd = vsize;
   } else {
     hsize = im->xsize;
-    vsize = (int)(0.5 + im->ysize * Value);
+    vsize = (i_img_dim)(0.5 + im->ysize * Value);
 
     if (vsize < 1) {
       vsize = 1;
@@ -775,23 +583,23 @@ i_scaleaxis(i_img *im, float Value, int Axis) {
     iEnd = hsize;
   }
   
-  new_img = i_img_empty_ch(NULL, hsize, vsize, im->channels);
+  new_img = i_img_8_new(hsize, vsize, im->channels);
   if (!new_img) {
     i_push_error(0, "cannot create output image");
     return NULL;
   }
   
   /* 1.4 is a magic number, setting it to 2 will cause rather blurred images */
-  LanczosWidthFactor = (Value >= 1) ? 1 : (int) (1.4/Value); 
+  LanczosWidthFactor = (Value >= 1) ? 1 : (i_img_dim) (1.4/Value); 
   lMax = LanczosWidthFactor << 1;
   
   l0 = mymalloc(lMax * sizeof(float));
   l1 = mymalloc(lMax * sizeof(float));
   
   for (j=0; j<jEnd; j++) {
-    OldLocation = ((float) j) / Value;
-    T = (int) (OldLocation);
-    F = OldLocation - (float) T;
+    OldLocation = ((double) j) / Value;
+    T = (i_img_dim) (OldLocation);
+    F = OldLocation - T;
     
     for (l = 0; l<lMax; l++) {
       l0[lMax-l-1] = Lanczos(((float) (lMax-l-1) + F) / (float) LanczosWidthFactor);
@@ -804,7 +612,7 @@ i_scaleaxis(i_img *im, float Value, int Axis) {
       t+=l0[l];
       t+=l1[l];
     }
-    t /= (float)LanczosWidthFactor;
+    t /= (double)LanczosWidthFactor;
     
     for(l=0; l<lMax; l++) {
       l0[l] /= t;
@@ -816,22 +624,53 @@ i_scaleaxis(i_img *im, float Value, int Axis) {
       for (i=0; i<iEnd; i++) {
 	for (k=0; k<im->channels; k++) PictureValue[k] = 0.0;
 	for (l=0; l<lMax; l++) {
-	  int mx = T-lMax+l+1;
-	  int Mx = T+l+1;
+	  i_img_dim mx = T-lMax+l+1;
+	  i_img_dim Mx = T+l+1;
 	  mx = (mx < 0) ? 0 : mx;
 	  Mx = (Mx >= im->xsize) ? im->xsize-1 : Mx;
 	  
 	  i_gpix(im, Mx, i, &val1);
 	  i_gpix(im, mx, i, &val2);
-	  
-	  for (k=0; k<im->channels; k++) {
-	    PictureValue[k] += l1[l]        * val1.channel[k];
-	    PictureValue[k] += l0[lMax-l-1] * val2.channel[k];
+
+	  if (has_alpha) {
+	    i_sample_t alpha1 = val1.channel[color_chans];
+	    i_sample_t alpha2 = val2.channel[color_chans];
+	    for (k=0; k < color_chans; k++) {
+	      PictureValue[k] += l1[l]        * val1.channel[k] * alpha1 / 255;
+	      PictureValue[k] += l0[lMax-l-1] * val2.channel[k] * alpha2 / 255;
+	    }
+	    PictureValue[color_chans] += l1[l] * val1.channel[color_chans];
+	    PictureValue[color_chans] += l0[lMax-l-1] * val2.channel[color_chans];
+	  }
+	  else {
+	    for (k=0; k<im->channels; k++) {
+	      PictureValue[k] += l1[l]        * val1.channel[k];
+	      PictureValue[k] += l0[lMax-l-1] * val2.channel[k];
+	    }
 	  }
 	}
-	for(k=0;k<im->channels;k++) {
-	  psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor));
-	  val.channel[k]=minmax(0,255,psave);
+
+	if (has_alpha) {
+	  float fa = PictureValue[color_chans] / LanczosWidthFactor;
+	  int alpha = minmax(0, 255, fa+0.5);
+	  if (alpha) {
+	    for (k = 0; k < color_chans; ++k) {
+	      psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor * 255 / fa));
+	      val.channel[k]=minmax(0,255,psave);
+	    }
+	    val.channel[color_chans] = alpha;
+	  }
+	  else {
+	    /* zero alpha, so the pixel has no color */
+	    for (k = 0; k < im->channels; ++k)
+	      val.channel[k] = 0;
+	  }
+	}
+	else {
+	  for(k=0;k<im->channels;k++) {
+	    psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor));
+	    val.channel[k]=minmax(0,255,psave);
+	  }
 	}
 	i_ppix(new_img, j, i, &val);
       }
@@ -841,21 +680,50 @@ i_scaleaxis(i_img *im, float Value, int Axis) {
       for (i=0; i<iEnd; i++) {
 	for (k=0; k<im->channels; k++) PictureValue[k] = 0.0;
 	for (l=0; l < lMax; l++) {
-	  int mx = T-lMax+l+1;
-	  int Mx = T+l+1;
+	  i_img_dim mx = T-lMax+l+1;
+	  i_img_dim Mx = T+l+1;
 	  mx = (mx < 0) ? 0 : mx;
 	  Mx = (Mx >= im->ysize) ? im->ysize-1 : Mx;
 
 	  i_gpix(im, i, Mx, &val1);
 	  i_gpix(im, i, mx, &val2);
-	  for (k=0; k<im->channels; k++) {
-	    PictureValue[k] += l1[l]        * val1.channel[k];
-	    PictureValue[k] += l0[lMax-l-1] * val2.channel[k]; 
+	  if (has_alpha) {
+	    i_sample_t alpha1 = val1.channel[color_chans];
+	    i_sample_t alpha2 = val2.channel[color_chans];
+	    for (k=0; k < color_chans; k++) {
+	      PictureValue[k] += l1[l]        * val1.channel[k] * alpha1 / 255;
+	      PictureValue[k] += l0[lMax-l-1] * val2.channel[k] * alpha2 / 255;
+	    }
+	    PictureValue[color_chans] += l1[l] * val1.channel[color_chans];
+	    PictureValue[color_chans] += l0[lMax-l-1] * val2.channel[color_chans];
+	  }
+	  else {
+	    for (k=0; k<im->channels; k++) {
+	      PictureValue[k] += l1[l]        * val1.channel[k];
+	      PictureValue[k] += l0[lMax-l-1] * val2.channel[k];
+	    }
 	  }
 	}
-	for (k=0; k<im->channels; k++) {
-	  psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor));
-	  val.channel[k] = minmax(0, 255, psave);
+	if (has_alpha) {
+	  float fa = PictureValue[color_chans] / LanczosWidthFactor;
+	  int alpha = minmax(0, 255, fa+0.5);
+	  if (alpha) {
+	    for (k = 0; k < color_chans; ++k) {
+	      psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor * 255 / fa));
+	      val.channel[k]=minmax(0,255,psave);
+	    }
+	    val.channel[color_chans] = alpha;
+	  }
+	  else {
+	    for (k = 0; k < im->channels; ++k)
+	      val.channel[k] = 0;
+	  }
+	}
+	else {
+	  for(k=0;k<im->channels;k++) {
+	    psave = (short)(0.5+(PictureValue[k] / LanczosWidthFactor));
+	    val.channel[k]=minmax(0,255,psave);
+	  }
 	}
 	i_ppix(new_img, i, j, &val);
       }
@@ -865,7 +733,7 @@ i_scaleaxis(i_img *im, float Value, int Axis) {
   myfree(l0);
   myfree(l1);
 
-  mm_log((1,"(%p) <- i_scaleaxis\n", new_img));
+  im_log((aIMCTX, 1,"(%p) <- i_scaleaxis\n", new_img));
 
   return new_img;
 }
@@ -883,20 +751,21 @@ nothing is gained by doing it in two steps
 
 
 i_img*
-i_scale_nn(i_img *im, float scx, float scy) {
+i_scale_nn(i_img *im, double scx, double scy) {
 
-  int nxsize,nysize,nx,ny;
+  i_img_dim nxsize,nysize,nx,ny;
   i_img *new_img;
   i_color val;
+  dIMCTXim(im);
 
-  mm_log((1,"i_scale_nn(im 0x%x,scx %.2f,scy %.2f)\n",im,scx,scy));
+  im_log((aIMCTX, 1,"i_scale_nn(im %p,scx %.2f,scy %.2f)\n",im,scx,scy));
 
-  nxsize = (int) ((float) im->xsize * scx);
+  nxsize = (i_img_dim) ((double) im->xsize * scx);
   if (nxsize < 1) {
     nxsize = 1;
     scx = 1.0 / im->xsize;
   }
-  nysize = (int) ((float) im->ysize * scy);
+  nysize = (i_img_dim) ((double) im->ysize * scy);
   if (nysize < 1) {
     nysize = 1;
     scy = 1.0 / im->ysize;
@@ -906,11 +775,11 @@ i_scale_nn(i_img *im, float scx, float scy) {
   new_img=i_img_empty_ch(NULL,nxsize,nysize,im->channels);
   
   for(ny=0;ny<nysize;ny++) for(nx=0;nx<nxsize;nx++) {
-    i_gpix(im,((float)nx)/scx,((float)ny)/scy,&val);
+    i_gpix(im,((double)nx)/scx,((double)ny)/scy,&val);
     i_ppix(new_img,nx,ny,&val);
   }
 
-  mm_log((1,"(0x%x) <- i_scale_nn\n",new_img));
+  im_log((aIMCTX, 1,"(%p) <- i_scale_nn\n",new_img));
 
   return new_img;
 }
@@ -928,7 +797,10 @@ For paletted images the palette is copied from the source.
 =cut
 */
 
-i_img *i_sametype(i_img *src, int xsize, int ysize) {
+i_img *
+i_sametype(i_img *src, i_img_dim xsize, i_img_dim ysize) {
+  dIMCTXim(src);
+
   if (src->type == i_direct_type) {
     if (src->bits == 8) {
       return i_img_empty_ch(NULL, xsize, ysize, src->channels);
@@ -971,7 +843,10 @@ For paletted images the equivalent direct type is returned.
 =cut
 */
 
-i_img *i_sametype_chans(i_img *src, int xsize, int ysize, int channels) {
+i_img *
+i_sametype_chans(i_img *src, i_img_dim xsize, i_img_dim ysize, int channels) {
+  dIMCTXim(src);
+
   if (src->bits == 8) {
     return i_img_empty_ch(NULL, xsize, ysize, channels);
   }
@@ -1009,11 +884,12 @@ The operators for this function are defined in L<stackmach.c>.
 i_img*
 i_transform(i_img *im, int *opx,int opxl,int *opy,int opyl,double parm[],int parmlen) {
   double rx,ry;
-  int nxsize,nysize,nx,ny;
+  i_img_dim nxsize,nysize,nx,ny;
   i_img *new_img;
   i_color val;
+  dIMCTXim(im);
   
-  mm_log((1,"i_transform(im 0x%x, opx 0x%x, opxl %d, opy 0x%x, opyl %d, parm 0x%x, parmlen %d)\n",im,opx,opxl,opy,opyl,parm,parmlen));
+  im_log((aIMCTX, 1,"i_transform(im %p, opx %p, opxl %d, opy %p, opyl %d, parm %p, parmlen %d)\n",im,opx,opxl,opy,opyl,parm,parmlen));
 
   nxsize = im->xsize;
   nysize = im->ysize ;
@@ -1035,7 +911,7 @@ i_transform(i_img *im, int *opx,int opxl,int *opy,int opyl,double parm[],int par
     i_ppix(new_img,nx,ny,&val);
   }
 
-  mm_log((1,"(0x%x) <- i_transform\n",new_img));
+  im_log((aIMCTX, 1,"(%p) <- i_transform\n",new_img));
   return new_img;
 }
 
@@ -1054,17 +930,20 @@ can return zero.
 
 float
 i_img_diff(i_img *im1,i_img *im2) {
-  int x,y,ch,xb,yb,chb;
+  i_img_dim x, y, xb, yb;
+  int ch, chb;
   float tdiff;
   i_color val1,val2;
+  dIMCTXim(im1);
 
-  mm_log((1,"i_img_diff(im1 0x%x,im2 0x%x)\n",im1,im2));
+  im_log((aIMCTX, 1,"i_img_diff(im1 %p,im2 %p)\n",im1,im2));
 
   xb=(im1->xsize<im2->xsize)?im1->xsize:im2->xsize;
   yb=(im1->ysize<im2->ysize)?im1->ysize:im2->ysize;
   chb=(im1->channels<im2->channels)?im1->channels:im2->channels;
 
-  mm_log((1,"i_img_diff: xb=%d xy=%d chb=%d\n",xb,yb,chb));
+  im_log((aIMCTX, 1,"i_img_diff: b=(" i_DFp ") chb=%d\n",
+	  i_DFcp(xb,yb), chb));
 
   tdiff=0;
   for(y=0;y<yb;y++) for(x=0;x<xb;x++) {
@@ -1073,7 +952,7 @@ i_img_diff(i_img *im1,i_img *im2) {
 
     for(ch=0;ch<chb;ch++) tdiff+=(val1.channel[ch]-val2.channel[ch])*(val1.channel[ch]-val2.channel[ch]);
   }
-  mm_log((1,"i_img_diff <- (%.2f)\n",tdiff));
+  im_log((aIMCTX, 1,"i_img_diff <- (%.2f)\n",tdiff));
   return tdiff;
 }
 
@@ -1094,17 +973,20 @@ This is like i_img_diff() but looks at floating point samples instead.
 
 double
 i_img_diffd(i_img *im1,i_img *im2) {
-  int x,y,ch,xb,yb,chb;
+  i_img_dim x, y, xb, yb;
+  int ch, chb;
   double tdiff;
   i_fcolor val1,val2;
+  dIMCTXim(im1);
 
-  mm_log((1,"i_img_diffd(im1 0x%x,im2 0x%x)\n",im1,im2));
+  im_log((aIMCTX, 1,"i_img_diffd(im1 %p,im2 %p)\n",im1,im2));
 
   xb=(im1->xsize<im2->xsize)?im1->xsize:im2->xsize;
   yb=(im1->ysize<im2->ysize)?im1->ysize:im2->ysize;
   chb=(im1->channels<im2->channels)?im1->channels:im2->channels;
 
-  mm_log((1,"i_img_diff: xb=%d xy=%d chb=%d\n",xb,yb,chb));
+  im_log((aIMCTX, 1,"i_img_diffd: b(" i_DFp ") chb=%d\n",
+	  i_DFcp(xb, yb), chb));
 
   tdiff=0;
   for(y=0;y<yb;y++) for(x=0;x<xb;x++) {
@@ -1116,21 +998,61 @@ i_img_diffd(i_img *im1,i_img *im2) {
       tdiff += sdiff * sdiff;
     }
   }
-  mm_log((1,"i_img_diffd <- (%.2f)\n",tdiff));
+  im_log((aIMCTX, 1,"i_img_diffd <- (%.2f)\n",tdiff));
 
   return tdiff;
 }
 
+int
+i_img_samef(i_img *im1,i_img *im2, double epsilon, char const *what) {
+  i_img_dim x,y,xb,yb;
+  int ch, chb;
+  i_fcolor val1,val2;
+  dIMCTXim(im1);
+
+  if (what == NULL)
+    what = "(null)";
+
+  im_log((aIMCTX,1,"i_img_samef(im1 %p,im2 %p, epsilon %g, what '%s')\n", im1, im2, epsilon, what));
+
+  xb=(im1->xsize<im2->xsize)?im1->xsize:im2->xsize;
+  yb=(im1->ysize<im2->ysize)?im1->ysize:im2->ysize;
+  chb=(im1->channels<im2->channels)?im1->channels:im2->channels;
+
+  im_log((aIMCTX, 1,"i_img_samef: b(" i_DFp ") chb=%d\n",
+	  i_DFcp(xb, yb), chb));
+
+  for(y = 0; y < yb; y++) {
+    for(x = 0; x < xb; x++) {
+      i_gpixf(im1, x, y, &val1);
+      i_gpixf(im2, x, y, &val2);
+      
+      for(ch = 0; ch < chb; ch++) {
+	double sdiff = val1.channel[ch] - val2.channel[ch];
+	if (fabs(sdiff) > epsilon) {
+	  im_log((aIMCTX, 1,"i_img_samef <- different %g @(" i_DFp ")\n",
+		  sdiff, i_DFcp(x, y)));
+	  return 0;
+	}
+      }
+    }
+  }
+  im_log((aIMCTX, 1,"i_img_samef <- same\n"));
+
+  return 1;
+}
+
 /* just a tiny demo of haar wavelets */
 
 i_img*
 i_haar(i_img *im) {
-  int mx,my;
-  int fx,fy;
-  int x,y;
-  int ch,c;
+  i_img_dim mx,my;
+  i_img_dim fx,fy;
+  i_img_dim x,y;
+  int ch;
   i_img *new_img,*new_img2;
   i_color val1,val2,dval1,dval2;
+  dIMCTXim(im);
   
   mx=im->xsize;
   my=im->ysize;
@@ -1143,7 +1065,6 @@ i_haar(i_img *im) {
   new_img=i_img_empty_ch(NULL,fx*2,fy*2,im->channels);
   new_img2=i_img_empty_ch(NULL,fx*2,fy*2,im->channels);
 
-  c=0; 
   for(y=0;y<my;y++) for(x=0;x<fx;x++) {
     i_gpix(im,x*2,y,&val1);
     i_gpix(im,x*2+1,y,&val2);
@@ -1183,13 +1104,13 @@ to indicate that it was more than max colors
 int
 i_count_colors(i_img *im,int maxc) {
   struct octt *ct;
-  int x,y;
+  i_img_dim x,y;
   int colorcnt;
   int channels[3];
   int *samp_chans;
   i_sample_t * samp;
-  int xsize = im->xsize; 
-  int ysize = im->ysize;
+  i_img_dim xsize = im->xsize; 
+  i_img_dim ysize = im->ysize;
   int samp_cnt = 3 * xsize;
 
   if (im->channels >= 3) {
@@ -1272,15 +1193,15 @@ hpsort(unsigned int n, unsigned *ra) {
 int
 i_get_anonymous_color_histo(i_img *im, unsigned int **col_usage, int maxc) {
   struct octt *ct;
-  int x,y;
+  i_img_dim x,y;
   int colorcnt;
   unsigned int *col_usage_it;
   i_sample_t * samp;
   int channels[3];
   int *samp_chans;
   
-  int xsize = im->xsize; 
-  int ysize = im->ysize;
+  i_img_dim xsize = im->xsize; 
+  i_img_dim ysize = im->ysize;
   int samp_cnt = 3 * xsize;
   ct = octt_new();
   
@@ -1318,388 +1239,6 @@ i_get_anonymous_color_histo(i_img *im, unsigned int **col_usage, int maxc) {
 /*
 =back
 
-=head2 8-bit per sample image internal functions
-
-These are the functions installed in an 8-bit per sample image.
-
-=over
-
-=item i_ppix_d(im, x, y, col)
-
-Internal function.
-
-This is the function kept in the i_f_ppix member of an i_img object.
-It does a normal store of a pixel into the image with range checking.
-
-Returns 0 if the pixel could be set, -1 otherwise.
-
-=cut
-*/
-static
-int
-i_ppix_d(i_img *im, int x, int y, const i_color *val) {
-  int ch;
-  
-  if ( x>-1 && x<im->xsize && y>-1 && y<im->ysize ) {
-    for(ch=0;ch<im->channels;ch++)
-      if (im->ch_mask&(1<<ch)) 
-	im->idata[(x+y*im->xsize)*im->channels+ch]=val->channel[ch];
-    return 0;
-  }
-  return -1; /* error was clipped */
-}
-
-/*
-=item i_gpix_d(im, x, y, &col)
-
-Internal function.
-
-This is the function kept in the i_f_gpix member of an i_img object.
-It does normal retrieval of a pixel from the image with range checking.
-
-Returns 0 if the pixel could be set, -1 otherwise.
-
-=cut
-*/
-static
-int 
-i_gpix_d(i_img *im, int x, int y, i_color *val) {
-  int ch;
-  if (x>-1 && x<im->xsize && y>-1 && y<im->ysize) {
-    for(ch=0;ch<im->channels;ch++) 
-      val->channel[ch]=im->idata[(x+y*im->xsize)*im->channels+ch];
-    return 0;
-  }
-  for(ch=0;ch<im->channels;ch++) val->channel[ch] = 0;
-  return -1; /* error was cliped */
-}
-
-/*
-=item i_glin_d(im, l, r, y, vals)
-
-Reads a line of data from the image, storing the pixels at vals.
-
-The line runs from (l,y) inclusive to (r,y) non-inclusive
-
-vals should point at space for (r-l) pixels.
-
-l should never be less than zero (to avoid confusion about where to
-put the pixels in vals).
-
-Returns the number of pixels copied (eg. if r, l or y is out of range)
-
-=cut
-*/
-static
-int
-i_glin_d(i_img *im, int l, int r, int y, i_color *vals) {
-  int ch, count, i;
-  unsigned char *data;
-  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
-    if (r > im->xsize)
-      r = im->xsize;
-    data = im->idata + (l+y*im->xsize) * im->channels;
-    count = r - l;
-    for (i = 0; i < count; ++i) {
-      for (ch = 0; ch < im->channels; ++ch)
-	vals[i].channel[ch] = *data++;
-    }
-    return count;
-  }
-  else {
-    return 0;
-  }
-}
-
-/*
-=item i_plin_d(im, l, r, y, vals)
-
-Writes a line of data into the image, using the pixels at vals.
-
-The line runs from (l,y) inclusive to (r,y) non-inclusive
-
-vals should point at (r-l) pixels.
-
-l should never be less than zero (to avoid confusion about where to
-get the pixels in vals).
-
-Returns the number of pixels copied (eg. if r, l or y is out of range)
-
-=cut
-*/
-static
-int
-i_plin_d(i_img *im, int l, int r, int y, const i_color *vals) {
-  int ch, count, i;
-  unsigned char *data;
-  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
-    if (r > im->xsize)
-      r = im->xsize;
-    data = im->idata + (l+y*im->xsize) * im->channels;
-    count = r - l;
-    for (i = 0; i < count; ++i) {
-      for (ch = 0; ch < im->channels; ++ch) {
-	if (im->ch_mask & (1 << ch)) 
-	  *data = vals[i].channel[ch];
-	++data;
-      }
-    }
-    return count;
-  }
-  else {
-    return 0;
-  }
-}
-
-/*
-=item i_ppixf_d(im, x, y, val)
-
-=cut
-*/
-static
-int
-i_ppixf_d(i_img *im, int x, int y, const i_fcolor *val) {
-  int ch;
-  
-  if ( x>-1 && x<im->xsize && y>-1 && y<im->ysize ) {
-    for(ch=0;ch<im->channels;ch++)
-      if (im->ch_mask&(1<<ch)) {
-	im->idata[(x+y*im->xsize)*im->channels+ch] = 
-          SampleFTo8(val->channel[ch]);
-      }
-    return 0;
-  }
-  return -1; /* error was clipped */
-}
-
-/*
-=item i_gpixf_d(im, x, y, val)
-
-=cut
-*/
-static
-int
-i_gpixf_d(i_img *im, int x, int y, i_fcolor *val) {
-  int ch;
-  if (x>-1 && x<im->xsize && y>-1 && y<im->ysize) {
-    for(ch=0;ch<im->channels;ch++) {
-      val->channel[ch] = 
-        Sample8ToF(im->idata[(x+y*im->xsize)*im->channels+ch]);
-    }
-    return 0;
-  }
-  return -1; /* error was cliped */
-}
-
-/*
-=item i_glinf_d(im, l, r, y, vals)
-
-Reads a line of data from the image, storing the pixels at vals.
-
-The line runs from (l,y) inclusive to (r,y) non-inclusive
-
-vals should point at space for (r-l) pixels.
-
-l should never be less than zero (to avoid confusion about where to
-put the pixels in vals).
-
-Returns the number of pixels copied (eg. if r, l or y is out of range)
-
-=cut
-*/
-static
-int
-i_glinf_d(i_img *im, int l, int r, int y, i_fcolor *vals) {
-  int ch, count, i;
-  unsigned char *data;
-  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
-    if (r > im->xsize)
-      r = im->xsize;
-    data = im->idata + (l+y*im->xsize) * im->channels;
-    count = r - l;
-    for (i = 0; i < count; ++i) {
-      for (ch = 0; ch < im->channels; ++ch)
-	vals[i].channel[ch] = Sample8ToF(*data++);
-    }
-    return count;
-  }
-  else {
-    return 0;
-  }
-}
-
-/*
-=item i_plinf_d(im, l, r, y, vals)
-
-Writes a line of data into the image, using the pixels at vals.
-
-The line runs from (l,y) inclusive to (r,y) non-inclusive
-
-vals should point at (r-l) pixels.
-
-l should never be less than zero (to avoid confusion about where to
-get the pixels in vals).
-
-Returns the number of pixels copied (eg. if r, l or y is out of range)
-
-=cut
-*/
-static
-int
-i_plinf_d(i_img *im, int l, int r, int y, const i_fcolor *vals) {
-  int ch, count, i;
-  unsigned char *data;
-  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
-    if (r > im->xsize)
-      r = im->xsize;
-    data = im->idata + (l+y*im->xsize) * im->channels;
-    count = r - l;
-    for (i = 0; i < count; ++i) {
-      for (ch = 0; ch < im->channels; ++ch) {
-	if (im->ch_mask & (1 << ch)) 
-	  *data = SampleFTo8(vals[i].channel[ch]);
-	++data;
-      }
-    }
-    return count;
-  }
-  else {
-    return 0;
-  }
-}
-
-/*
-=item i_gsamp_d(i_img *im, int l, int r, int y, i_sample_t *samps, int *chans, int chan_count)
-
-Reads sample values from im for the horizontal line (l, y) to (r-1,y)
-for the channels specified by chans, an array of int with chan_count
-elements.
-
-Returns the number of samples read (which should be (r-l) * bits_set(chan_mask)
-
-=cut
-*/
-static
-int
-i_gsamp_d(i_img *im, int l, int r, int y, i_sample_t *samps, 
-              const int *chans, int chan_count) {
-  int ch, count, i, w;
-  unsigned char *data;
-
-  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
-    if (r > im->xsize)
-      r = im->xsize;
-    data = im->idata + (l+y*im->xsize) * im->channels;
-    w = r - l;
-    count = 0;
-
-    if (chans) {
-      /* make sure we have good channel numbers */
-      for (ch = 0; ch < chan_count; ++ch) {
-        if (chans[ch] < 0 || chans[ch] >= im->channels) {
-          i_push_errorf(0, "No channel %d in this image", chans[ch]);
-          return 0;
-        }
-      }
-      for (i = 0; i < w; ++i) {
-        for (ch = 0; ch < chan_count; ++ch) {
-          *samps++ = data[chans[ch]];
-          ++count;
-        }
-        data += im->channels;
-      }
-    }
-    else {
-      if (chan_count <= 0 || chan_count > im->channels) {
-	i_push_errorf(0, "chan_count %d out of range, must be >0, <= channels", 
-		      chan_count);
-	return 0;
-      }
-      for (i = 0; i < w; ++i) {
-        for (ch = 0; ch < chan_count; ++ch) {
-          *samps++ = data[ch];
-          ++count;
-        }
-        data += im->channels;
-      }
-    }
-
-    return count;
-  }
-  else {
-    return 0;
-  }
-}
-
-/*
-=item i_gsampf_d(i_img *im, int l, int r, int y, i_fsample_t *samps, int *chans, int chan_count)
-
-Reads sample values from im for the horizontal line (l, y) to (r-1,y)
-for the channels specified by chan_mask, where bit 0 is the first
-channel.
-
-Returns the number of samples read (which should be (r-l) * bits_set(chan_mask)
-
-=cut
-*/
-static
-int
-i_gsampf_d(i_img *im, int l, int r, int y, i_fsample_t *samps, 
-           const int *chans, int chan_count) {
-  int ch, count, i, w;
-  unsigned char *data;
-  for (ch = 0; ch < chan_count; ++ch) {
-    if (chans[ch] < 0 || chans[ch] >= im->channels) {
-      i_push_errorf(0, "No channel %d in this image", chans[ch]);
-    }
-  }
-  if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
-    if (r > im->xsize)
-      r = im->xsize;
-    data = im->idata + (l+y*im->xsize) * im->channels;
-    w = r - l;
-    count = 0;
-
-    if (chans) {
-      /* make sure we have good channel numbers */
-      for (ch = 0; ch < chan_count; ++ch) {
-        if (chans[ch] < 0 || chans[ch] >= im->channels) {
-          i_push_errorf(0, "No channel %d in this image", chans[ch]);
-          return 0;
-        }
-      }
-      for (i = 0; i < w; ++i) {
-        for (ch = 0; ch < chan_count; ++ch) {
-          *samps++ = Sample8ToF(data[chans[ch]]);
-          ++count;
-        }
-        data += im->channels;
-      }
-    }
-    else {
-      if (chan_count <= 0 || chan_count > im->channels) {
-	i_push_errorf(0, "chan_count %d out of range, must be >0, <= channels", 
-		      chan_count);
-	return 0;
-      }
-      for (i = 0; i < w; ++i) {
-        for (ch = 0; ch < chan_count; ++ch) {
-          *samps++ = Sample8ToF(data[ch]);
-          ++count;
-        }
-        data += im->channels;
-      }
-    }
-    return count;
-  }
-  else {
-    return 0;
-  }
-}
-
-/*
-=back
-
 =head2 Image method wrappers
 
 These functions provide i_fsample_t functions in terms of their
@@ -1707,12 +1246,12 @@ i_sample_t versions.
 
 =over
 
-=item i_ppixf_fp(i_img *im, int x, int y, i_fcolor *pix)
+=item i_ppixf_fp(i_img *im, i_img_dim x, i_img_dim y, i_fcolor *pix)
 
 =cut
 */
 
-int i_ppixf_fp(i_img *im, int x, int y, const i_fcolor *pix) {
+int i_ppixf_fp(i_img *im, i_img_dim x, i_img_dim y, const i_fcolor *pix) {
   i_color temp;
   int ch;
 
@@ -1723,15 +1262,15 @@ int i_ppixf_fp(i_img *im, int x, int y, const i_fcolor *pix) {
 }
 
 /*
-=item i_gpixf_fp(i_img *im, int x, int y, i_fcolor *pix)
+=item i_gpixf_fp(i_img *im, i_img_dim x, i_img_dim y, i_fcolor *pix)
 
 =cut
 */
-int i_gpixf_fp(i_img *im, int x, int y, i_fcolor *pix) {
+int i_gpixf_fp(i_img *im, i_img_dim x, i_img_dim y, i_fcolor *pix) {
   i_color temp;
   int ch;
 
-  if (i_gpix(im, x, y, &temp)) {
+  if (i_gpix(im, x, y, &temp) == 0) {
     for (ch = 0; ch < im->channels; ++ch)
       pix->channel[ch] = Sample8ToF(temp.channel[ch]);
     return 0;
@@ -1741,19 +1280,21 @@ int i_gpixf_fp(i_img *im, int x, int y, i_fcolor *pix) {
 }
 
 /*
-=item i_plinf_fp(i_img *im, int l, int r, int y, i_fcolor *pix)
+=item i_plinf_fp(i_img *im, i_img_dim l, i_img_dim r, i_img_dim y, i_fcolor *pix)
 
 =cut
 */
-int i_plinf_fp(i_img *im, int l, int r, int y, const i_fcolor *pix) {
+i_img_dim
+i_plinf_fp(i_img *im, i_img_dim l, i_img_dim r, i_img_dim y, const i_fcolor *pix) {
   i_color *work;
 
   if (y >= 0 && y < im->ysize && l < im->xsize && l >= 0) {
     if (r > im->xsize)
       r = im->xsize;
     if (r > l) {
-      int ret;
-      int i, ch;
+      i_img_dim ret;
+      i_img_dim i;
+      int ch;
       work = mymalloc(sizeof(i_color) * (r-l));
       for (i = 0; i < r-l; ++i) {
         for (ch = 0; ch < im->channels; ++ch) 
@@ -1774,19 +1315,21 @@ int i_plinf_fp(i_img *im, int l, int r, int y, const i_fcolor *pix) {
 }
 
 /*
-=item i_glinf_fp(i_img *im, int l, int r, int y, i_fcolor *pix)
+=item i_glinf_fp(i_img *im, i_img_dim l, i_img_dim r, i_img_dim y, i_fcolor *pix)
 
 =cut
 */
-int i_glinf_fp(i_img *im, int l, int r, int y, i_fcolor *pix) {
+i_img_dim
+i_glinf_fp(i_img *im, i_img_dim l, i_img_dim r, i_img_dim y, i_fcolor *pix) {
   i_color *work;
 
   if (y >= 0 && y < im->ysize && l < im->xsize && l >= 0) {
     if (r > im->xsize)
       r = im->xsize;
     if (r > l) {
-      int ret;
-      int i, ch;
+      i_img_dim ret;
+      i_img_dim i;
+      int ch;
       work = mymalloc(sizeof(i_color) * (r-l));
       ret = i_plin(im, l, r, y, work);
       for (i = 0; i < r-l; ++i) {
@@ -1807,11 +1350,13 @@ int i_glinf_fp(i_img *im, int l, int r, int y, i_fcolor *pix) {
 }
 
 /*
-=item i_gsampf_fp(i_img *im, int l, int r, int y, i_fsample_t *samp, int *chans, int chan_count)
+=item i_gsampf_fp(i_img *im, i_img_dim l, i_img_dim r, i_img_dim y, i_fsample_t *samp, int *chans, int chan_count)
 
 =cut
 */
-int i_gsampf_fp(i_img *im, int l, int r, int y, i_fsample_t *samp, 
+
+i_img_dim
+i_gsampf_fp(i_img *im, i_img_dim l, i_img_dim r, i_img_dim y, i_fsample_t *samp, 
                 int const *chans, int chan_count) {
   i_sample_t *work;
 
@@ -1819,8 +1364,8 @@ int i_gsampf_fp(i_img *im, int l, int r, int y, i_fsample_t *samp,
     if (r > im->xsize)
       r = im->xsize;
     if (r > l) {
-      int ret;
-      int i;
+      i_img_dim ret;
+      i_img_dim i;
       work = mymalloc(sizeof(i_sample_t) * (r-l));
       ret = i_gsamp(im, l, r, y, work, chans, chan_count);
       for (i = 0; i < ret; ++i) {
@@ -1915,9 +1460,11 @@ int i_findcolor_forward(i_img *im, const i_color *color, i_palidx *entry) {
 =cut
 */
 
-int 
-i_gsamp_bits_fb(i_img *im, int l, int r, int y, unsigned *samps, 
+i_img_dim
+i_gsamp_bits_fb(i_img *im, i_img_dim l, i_img_dim r, i_img_dim y, unsigned *samps, 
 		const int *chans, int chan_count, int bits) {
+  dIMCTXim(im);
+
   if (bits < 1 || bits > 32) {
     i_push_error(0, "Invalid bits, must be 1..32");
     return -1;
@@ -1925,7 +1472,8 @@ i_gsamp_bits_fb(i_img *im, int l, int r, int y, unsigned *samps,
 
   if (y >=0 && y < im->ysize && l < im->xsize && l >= 0) {
     double scale;
-    int ch, count, i, w;
+    int ch;
+    i_img_dim count, i, w;
     
     if (bits == 32)
       scale = 4294967295.0;
@@ -1941,7 +1489,7 @@ i_gsamp_bits_fb(i_img *im, int l, int r, int y, unsigned *samps,
       /* make sure we have good channel numbers */
       for (ch = 0; ch < chan_count; ++ch) {
         if (chans[ch] < 0 || chans[ch] >= im->channels) {
-          i_push_errorf(0, "No channel %d in this image", chans[ch]);
+          im_push_errorf(aIMCTX, 0, "No channel %d in this image", chans[ch]);
           return -1;
         }
       }
@@ -1977,194 +1525,6 @@ i_gsamp_bits_fb(i_img *im, int l, int r, int y, unsigned *samps,
   }
 }
 
-/*
-=back
-
-=head2 Stream reading and writing wrapper functions
-
-=over
-
-=item i_gen_reader(i_gen_read_data *info, char *buf, int length)
-
-Performs general read buffering for file readers that permit reading
-to be done through a callback.
-
-The final callback gets two parameters, a I<need> value, and a I<want>
-value, where I<need> is the amount of data that the file library needs
-to read, and I<want> is the amount of space available in the buffer
-maintained by these functions.
-
-This means if you need to read from a stream that you don't know the
-length of, you can return I<need> bytes, taking the performance hit of
-possibly expensive callbacks (eg. back to perl code), or if you are
-reading from a stream where it doesn't matter if some data is lost, or
-if the total length of the stream is known, you can return I<want>
-bytes.
-
-=cut 
-*/
-
-int
-i_gen_reader(i_gen_read_data *gci, char *buf, int length) {
-  int total;
-
-  if (length < gci->length - gci->cpos) {
-    /* simplest case */
-    memcpy(buf, gci->buffer+gci->cpos, length);
-    gci->cpos += length;
-    return length;
-  }
-  
-  total = 0;
-  memcpy(buf, gci->buffer+gci->cpos, gci->length-gci->cpos);
-  total  += gci->length - gci->cpos;
-  length -= gci->length - gci->cpos;
-  buf    += gci->length - gci->cpos;
-  if (length < (int)sizeof(gci->buffer)) {
-    int did_read;
-    int copy_size;
-    while (length
-	   && (did_read = (gci->cb)(gci->userdata, gci->buffer, length, 
-				    sizeof(gci->buffer))) > 0) {
-      gci->cpos = 0;
-      gci->length = did_read;
-
-      copy_size = i_min(length, gci->length);
-      memcpy(buf, gci->buffer, copy_size);
-      gci->cpos += copy_size;
-      buf += copy_size;
-      total += copy_size;
-      length -= copy_size;
-    }
-  }
-  else {
-    /* just read the rest - too big for our buffer*/
-    int did_read;
-    while ((did_read = (gci->cb)(gci->userdata, buf, length, length)) > 0) {
-      length -= did_read;
-      total += did_read;
-      buf += did_read;
-    }
-  }
-  return total;
-}
-
-/*
-=item i_gen_read_data_new(i_read_callback_t cb, char *userdata)
-
-For use by callback file readers to initialize the reader buffer.
-
-Allocates, initializes and returns the reader buffer.
-
-See also L<image.c/free_gen_read_data> and L<image.c/i_gen_reader>.
-
-=cut
-*/
-i_gen_read_data *
-i_gen_read_data_new(i_read_callback_t cb, char *userdata) {
-  i_gen_read_data *self = mymalloc(sizeof(i_gen_read_data));
-  self->cb = cb;
-  self->userdata = userdata;
-  self->length = 0;
-  self->cpos = 0;
-
-  return self;
-}
-
-/*
-=item i_free_gen_read_data(i_gen_read_data *)
-
-Cleans up.
-
-=cut
-*/
-void i_free_gen_read_data(i_gen_read_data *self) {
-  myfree(self);
-}
-
-/*
-=item i_gen_writer(i_gen_write_data *info, char const *data, int size)
-
-Performs write buffering for a callback based file writer.
-
-Failures are considered fatal, if a write fails then data will be
-dropped.
-
-=cut
-*/
-int 
-i_gen_writer(
-i_gen_write_data *self, 
-char const *data, 
-int size)
-{
-  if (self->filledto && self->filledto+size > self->maxlength) {
-    if (self->cb(self->userdata, self->buffer, self->filledto)) {
-      self->filledto = 0;
-    }
-    else {
-      self->filledto = 0;
-      return 0;
-    }
-  }
-  if (self->filledto+size <= self->maxlength) {
-    /* just save it */
-    memcpy(self->buffer+self->filledto, data, size);
-    self->filledto += size;
-    return 1;
-  }
-  /* doesn't fit - hand it off */
-  return self->cb(self->userdata, data, size);
-}
-
-/*
-=item i_gen_write_data_new(i_write_callback_t cb, char *userdata, int max_length)
-
-Allocates and initializes the data structure used by i_gen_writer.
-
-This should be released with L<image.c/i_free_gen_write_data>
-
-=cut
-*/
-i_gen_write_data *i_gen_write_data_new(i_write_callback_t cb, 
-				       char *userdata, int max_length)
-{
-  i_gen_write_data *self = mymalloc(sizeof(i_gen_write_data));
-  self->cb = cb;
-  self->userdata = userdata;
-  self->maxlength = i_min(max_length, sizeof(self->buffer));
-  if (self->maxlength < 0)
-    self->maxlength = sizeof(self->buffer);
-  self->filledto = 0;
-
-  return self;
-}
-
-/*
-=item i_free_gen_write_data(i_gen_write_data *info, int flush)
-
-Cleans up the write buffer.
-
-Will flush any left-over data if I<flush> is non-zero.
-
-Returns non-zero if flush is zero or if info->cb() returns non-zero.
-
-Return zero only if flush is non-zero and info->cb() returns zero.
-ie. if it fails.
-
-=cut
-*/
-
-int i_free_gen_write_data(i_gen_write_data *info, int flush)
-{
-  int result = !flush || 
-    info->filledto == 0 ||
-    info->cb(info->userdata, info->buffer, info->filledto);
-  myfree(info);
-
-  return result;
-}
-
 struct magic_entry {
   unsigned char *magic;
   size_t magic_size;
@@ -2267,6 +1627,14 @@ i_test_format_probe(io_glue *data, int length) {
 
     /* bzip2 compressed */
     FORMAT_ENTRY("BZh", "bzip2"),
+
+    /* WEBP
+       http://code.google.com/speed/webp/docs/riff_container.html */
+    FORMAT_ENTRY2("RIFF    WEBP", "webp", "xxxx    xxxx"),
+
+    /* JPEG 2000 
+       This might match a little loosely */
+    FORMAT_ENTRY("\x00\x00\x00\x0CjP  \x0D\x0A\x87\x0A", "jp2"),
   };
   static const struct magic_entry more_formats[] = {
     /* these were originally both listed as ico, but cur files can
@@ -2281,10 +1649,17 @@ i_test_format_probe(io_glue *data, int length) {
   unsigned char head[18];
   ssize_t rc;
 
-  io_glue_commit_types(data);
-  rc = data->readcb(data, head, 18);
+  rc = i_io_peekn(data, head, 18);
   if (rc == -1) return NULL;
-  data->seekcb(data, -rc, SEEK_CUR);
+#if 0
+  {
+    int i;
+    fprintf(stderr, "%d bytes -", (int)rc);
+    for (i = 0; i < rc; ++i)
+      fprintf(stderr, " %02x", head[i]);
+    fprintf(stderr, "\n");
+  }
+#endif
 
   for(i=0; i<sizeof(formats)/sizeof(formats[0]); i++) { 
     struct magic_entry const *entry = formats + i;
@@ -2310,10 +1685,13 @@ i_test_format_probe(io_glue *data, int length) {
 /*
 =item i_img_is_monochrome(img, &zero_is_white)
 
+=category Image Information
+
 Tests an image to check it meets our monochrome tests.
 
 The idea is that a file writer can use this to test where it should
-write the image in whatever bi-level format it uses, eg. pbm for pnm.
+write the image in whatever bi-level format it uses, eg. C<pbm> for
+C<pnm>.
 
 For performance of encoders we require monochrome images:
 
@@ -2325,12 +1703,12 @@ be paletted
 
 =item *
 
-have a palette of two colors, containing only (0,0,0) and
-(255,255,255) in either order.
+have a palette of two colors, containing only C<(0,0,0)> and
+C<(255,255,255)> in either order.
 
 =back
 
-zero_is_white is set to non-zero iff the first palette entry is white.
+C<zero_is_white> is set to non-zero if the first palette entry is white.
 
 =cut
 */
@@ -2382,45 +1760,57 @@ i_img_is_monochrome(i_img *im, int *zero_is_white) {
 /*
 =item i_get_file_background(im, &bg)
 
+=category Files
+
 Retrieve the file write background color tag from the image.
 
-If not present, returns black.
+If not present, C<bg> is set to black.
+
+Returns 1 if the C<i_background> tag was found and valid.
 
 =cut
 */
 
-void
+int
 i_get_file_background(i_img *im, i_color *bg) {
-  if (!i_tags_get_color(&im->tags, "i_background", 0, bg)) {
+  int result = i_tags_get_color(&im->tags, "i_background", 0, bg);
+  if (!result) {
     /* black default */
     bg->channel[0] = bg->channel[1] = bg->channel[2] = 0;
   }
   /* always full alpha */
   bg->channel[3] = 255;
+
+  return result;
 }
 
 /*
 =item i_get_file_backgroundf(im, &bg)
 
+=category Files
+
 Retrieve the file write background color tag from the image as a
 floating point color.
 
 Implemented in terms of i_get_file_background().
 
-If not present, returns black.
+If not present, C<bg> is set to black.
+
+Returns 1 if the C<i_background> tag was found and valid.
 
 =cut
 */
 
-void
+int
 i_get_file_backgroundf(i_img *im, i_fcolor *fbg) {
   i_color bg;
-
-  i_get_file_background(im, &bg);
+  int result = i_get_file_background(im, &bg);
   fbg->rgba.r = Sample8ToF(bg.rgba.r);
   fbg->rgba.g = Sample8ToF(bg.rgba.g);
   fbg->rgba.b = Sample8ToF(bg.rgba.b);
   fbg->rgba.a = 1.0;
+
+  return result;
 }
 
 /*
@@ -2430,7 +1820,7 @@ i_get_file_backgroundf(i_img *im, i_fcolor *fbg) {
 
 Arnar M. Hrafnkelsson <addi@umich.edu>
 
-Tony Cook <tony@develop-help.com>
+Tony Cook <tonyc@cpan.org>
 
 =head1 SEE ALSO