- In some cases when an error occurs reading those parts of a JPEG

[imager.git] / quant.c

diff --git a/quant.c b/quant.c
index 51524cd59b66113ff56662baf81b371df708a98d..52942d10c3d3e31642fbefd995a8389c4b3d51ab 100644 (file)
--- a/quant.c
+++ b/quant.c
@@ -2,10 +2,11 @@
    currently only used by gif.c, but maybe we'll support producing 
    8-bit (or bigger indexed) png files at some point
 */
-#include "image.h"
+#include "imager.h"
 
 static void makemap_addi(i_quantize *, i_img **imgs, int count);
 static void makemap_mediancut(i_quantize *, i_img **imgs, int count);
+static void makemap_mono(i_quantize *);
 
 static
 void
@@ -26,8 +27,20 @@ setcol(i_color *cl,unsigned char r,unsigned char g,unsigned char b,unsigned char
    handle multiple colour maps.
 */
 
+/*
+=item i_quant_makemap(quant, imgs, count)
+
+=category Image quantization
+
+Analyzes the I<count> images in I<imgs> according to the rules in
+I<quant> to build a color map (optimal or not depending on
+quant->make_colors).
+
+=cut
+*/
+
 void
-quant_makemap(i_quantize *quant, i_img **imgs, int count) {
+i_quant_makemap(i_quantize *quant, i_img **imgs, int count) {
 
   if (quant->translate == pt_giflib) {
     /* giflib does it's own color table generation */
@@ -59,6 +72,10 @@ quant_makemap(i_quantize *quant, i_img **imgs, int count) {
     makemap_mediancut(quant, imgs, count);
     break;
 
+  case mc_mono:
+    makemap_mono(quant);
+    break;
+
   case mc_addi:
   default:
     makemap_addi(quant, imgs, count);
@@ -70,11 +87,27 @@ static void translate_closest(i_quantize *, i_img *, i_palidx *);
 static void translate_errdiff(i_quantize *, i_img *, i_palidx *);
 static void translate_addi(i_quantize *, i_img *, i_palidx *);
 
-/* Quantize the image given the palette in quant.
+/*
+=item i_quant_translate(quant, img)
+
+=category Image quantization
+
+Quantize the image given the palette in quant.
+
+On success returns a pointer to a memory block of img->xsize *
+img->ysize i_palidx entries.
+
+On failure returns NULL.
+
+You should call myfree() on the returned block when you're done with
+it.
 
-   The giflib quantizer ignores the palette.
+This function will fail if the supplied palette contains no colors.
+
+=cut
 */
-i_palidx *quant_translate(i_quantize *quant, i_img *img) {
+i_palidx *
+i_quant_translate(i_quantize *quant, i_img *img) {
   i_palidx *result;
   int bytes;
 
@@ -588,7 +621,8 @@ makemap_mediancut(i_quantize *quant, i_img **imgs, int count) {
     color_count = 1;
     
     while (color_count < quant->mc_size) {
-      int max_index, max_ch; /* index/channel with biggest spread */
+      /* initialized to avoid compiler warnings */
+      int max_index = 0, max_ch = 0; /* index/channel with biggest spread */
       int max_size;
       medcut_partition *workpart;
       int cum_total;
@@ -668,6 +702,19 @@ makemap_mediancut(i_quantize *quant, i_img **imgs, int count) {
   i_mempool_destroy(&mp);
 }
 
+static void
+makemap_mono(i_quantize *quant) {
+  quant->mc_colors[0].rgba.r = 0;
+  quant->mc_colors[0].rgba.g = 0;
+  quant->mc_colors[0].rgba.b = 0;
+  quant->mc_colors[0].rgba.a = 255;
+  quant->mc_colors[1].rgba.r = 255;
+  quant->mc_colors[1].rgba.g = 255;
+  quant->mc_colors[1].rgba.b = 255;
+  quant->mc_colors[1].rgba.a = 255;
+  quant->mc_count = 2;
+}
+
 #define pboxjump 32
 
 /* Define one of the following 4 symbols to choose a colour search method
@@ -1059,7 +1106,7 @@ static int rand2dist_find(i_color val, i_quantize *quant, i_dists *dists, int in
 #endif
 
 static void translate_addi(i_quantize *quant, i_img *img, i_palidx *out) {
-  int x, y, i, k, bst_idx;
+  int x, y, i, k, bst_idx = 0;
   i_color val;
   int pixdev = quant->perturb;
   CF_VARS;
@@ -1156,7 +1203,7 @@ translate_errdiff(i_quantize *quant, i_img *img, i_palidx *out) {
   int errw;
   int difftotal;
   int x, y, dx, dy;
-  int bst_idx;
+  int bst_idx = 0;
   CF_VARS;
 
   if ((quant->errdiff & ed_mask) == ed_custom) {
@@ -1438,7 +1485,21 @@ static void transparent_threshold(i_quantize *, i_palidx *, i_img *, i_palidx);
 static void transparent_errdiff(i_quantize *, i_palidx *, i_img *, i_palidx);
 static void transparent_ordered(i_quantize *, i_palidx *, i_img *, i_palidx);
 
-void quant_transparent(i_quantize *quant, i_palidx *data, i_img *img,
+/*
+=item i_quant_transparent(quant, data, img, trans_index)
+
+=category Image quantization
+
+Dither the alpha channel on I<img> into the palette indexes in
+I<data>.  Pixels to be transparent are replaced with I<trans_pixel>.
+
+The method used depends on the tr_* members of quant.
+
+=cut
+*/
+
+void 
+i_quant_transparent(i_quantize *quant, i_palidx *data, i_img *img,
                       i_palidx trans_index)
 {
   switch (quant->transp) {