=head1 NAME
-Imager::interface.pod - decribes the C level virtual image interface
+Imager::interface.pod - describes the C level virtual image interface
=head1 SYNOPSIS
Some other possible virtual images:
+=for stopwords GIMP Photoshop
+
=over
=item *
image alpha combining, where the combining function can be specified
-(see the layer modes in graphical editors like the GIMP or photoshop.
+(see the layer modes in graphical editors like the GIMP or Photoshop.
=back
=over
-=item channels
+=item *
-the number of samples kept for each pixel in the image. For paletted
-images the samples are kept for each entry in the palette.
+C<channels> - the number of samples kept for each pixel in the image.
+For paletted images the samples are kept for each entry in the
+palette.
-=item xsize, ysize
+=item *
-the dimensions of the image in pixels.
+C<xsize>, C<ysize> - the dimensions of the image in pixels.
-=item bytes
+=item *
-the number of bytes of data kept for the image. Zero for virtual
-images. Does not include the space required for the palette for
-paletted images.
+C<bytes> - the number of bytes of data kept for the image. Zero for
+virtual images. Does not include the space required for the palette
+for paletted images.
-=item ch_mask
+=item *
-controls which samples will be written to for direct images.
+C<ch_mask> - controls which samples will be written to for direct
+images.
-=item bits
+=item *
-the number of bits kept for each sample. There are enum values
-i_8_bits, i_16_bits and i_double_bits (64).
+C<bits> - the number of bits kept for each sample. There are enum
+values i_8_bits, i_16_bits and i_double_bits (64).
-=item type
+=item *
-the type of image, either i_direct_type or i_palette_type. Direct
-images keep the samples for every pixel image, while i_palette_type
-images keep an index into a color table for each pixel.
+C<type> - the type of image, either i_direct_type or i_palette_type.
+Direct images keep the samples for every pixel image, while
+i_palette_type images keep an index into a color table for each pixel.
-=item virtual
+=item *
-whether the image keeps any pixel data. If this is non-zero then
-idata points to image data, otherwise it points to implementation
-defined data, though ext_data is more likely to be used for that.
+C<virtual> - whether the image keeps any pixel data. If this is
+non-zero then C<idata> points to image data, otherwise it points to
+implementation defined data, though C<ext_data> is more likely to be
+used for that.
-=item idata
+=item *
-image data. If the image is 8-bit direct, non-virtual, then this
-consists of each sample of the image stored one after another,
-otherwise it is implementation defined.
+C<idata> - image data. If the image is 8-bit direct, non-virtual,
+then this consists of each sample of the image stored one after
+another, otherwise it is implementation defined.
-=item tags
+=item *
-will be used to store meta-data for an image, eg. tags from a TIFF
-file, or animation information from a GIF file. This should be
+C<tags> - will be used to store meta-data for an image, eg. tags from
+a TIFF file, or animation information from a GIF file. This should be
initialized with a call to i_tags_new() in your image constructor if
creating a new image type.
-=item ext_data
+=item *
-for internal use of image types. This is not released by the standard
-i_img_exorcise() function. If you create a new image type and want to
-store a pointer to allocated memory here you should point i_f_destroy
-at a function that will release the data.
+C<ext_data> - for internal use of image types. This is not released
+by the standard i_img_exorcise() function. If you create a new image
+type and want to store a pointer to allocated memory here you should
+point i_f_destroy at a function that will release the data.
=back
=over
-=item i_f_ppix(im, x, y, color)
+=item i_f_ppix(im,x,y,color)
-=item i_f_ppixf(im, x, y, fcolor)
+=item i_f_ppixf(im,x,y,fcolor)
stores the specified color at pixel (x,y) in the image. If the pixel
can be stored return 0, otherwise -1. An image type may choose to
return 0 under some circumstances, eg. writing to a masked area of an
-image. The color or fcolor always contains the actual samples to be
+image. The C<color> or C<fcolor> always contains the actual samples to be
written, rather than a palette index.
-=item i_f_plin(im, l, r, y, colors)
+=item i_f_plin(im,l,r,y,colors)
-=item i_f_plinf(im, l, r, y, fcolors)
+=item i_f_plinf(im,l,r,y,fcolors)
stores (r-l) pixels at positions (l,y) ... (r-1, y) from the array
-specified by colors (or fcolors). Returns the number of pixels
-written to. If l is negative it will return 0. If r > im->xsize then
-only (im->xsize - l) will be written.
+specified by C<colors> (or C<fcolors>). Returns the number of pixels
+written to. If l is negative it will return 0. If C<< r > im->xsize
+>> then only C<< (im->xsize - l) >> will be written.
-=item i_f_gpix(im, x, y, color)
+=item i_f_gpix(im,x,y,color)
-=item i_f_gpixf(im, x, y, fcolor)
+=item i_f_gpixf(im,x,y,fcolor)
retrieves a single pixel from position (x,y). This returns the
samples rather than the index for paletted images.
-=item i_f_glin(im, l, r, y, colors)
+=item i_f_glin(im,l,r,y,colors)
-=item i_f_glinf(im, l, r, y, fcolors)
+=item i_f_glinf(im,l,r,y,fcolors)
retrieves (r-l) pixels from positions (l, y) through (r-1, y) into the
array specified by colors. Returns the number of pixels retrieved.
-If l < 0 no pixels are retrieved. If r > im->xsize then pixels (l, y)
-... (im->xsize-1, y) are retrieved. Retrieves the samples rather than
-the color indexes for paletted images.
+If l < 0 no pixels are retrieved. If C<< r > im->xsize >> then pixels
+C<< (l, y) >> ... C<< (im->xsize-1, y) >> are retrieved. Retrieves
+the samples rather than the color indexes for paletted images.
-=item i_f_gsamp(im, l, r, y, samples, chans, chan_count)
+=item i_f_gsamp(im,l,r,y,samples,chans,chan_count)
-=item i_f_gsampf(im, l, r, y, fsamples, chans, chan_count)
+=item i_f_gsampf(im,l,r,y,fsamples,chans,chan_count)
-Retrieves samples from channels specified by chans (for length
-chan_count) from pixels at positions (l,y) ... (r-1, y). If chans is
-NULL then samples from channels 0 ... chan_count-1 will be retrieved.
-Returns the number of sample retrieved (_not_ the number of channels).
-If a channel in chans is not present in the image or l < 0, returns 0.
-If r > im->xsize, then the samples from (l,y) ... (im->xsize-1, y) are
-returned.
+Retrieves samples from channels specified by C<chans> (for length
+C<chan_count>) from pixels at positions (l,y) ... (r-1, y). If
+C<chans> is NULL then samples from channels 0 ... C<chan_count-1> will
+be retrieved. Returns the number of sample retrieved (I<not> the
+number of channels). If a channel in C<chans> is not present in the
+image or l < 0, returns 0. If C<< r > im->xsize >>, then the samples
+from C<(l,y)> ... C<< (im->xsize-1, y) >> are returned.
=back
=over
-=item i_f_gpal(im, l, r, y, vals)
+=item i_f_gpal(im,l,r,y,vals)
Retrieves color indexes from the image for pixels (l, y) ... (r-1, y)
-into vals. Returns the number of indexes retrieved.
+into C<vals>. Returns the number of indexes retrieved.
-=item i_f_ppal(im, l, r, y, vals)
+=item i_f_ppal(im,l,r,y,vals)
Stores color indexes into the image for pixels (l, y) ... (r-1, y)
-from vals. Returns the number of indexes retrieved. If indices are
+from C<vals>. Returns the number of indexes retrieved. If indexes are
outside the range of the images palette, then you may have problems
reading those pixels with i_gpix() or i_glin().
-=item i_f_addcolors(im, colors, count)
+=item i_f_addcolors(im,colors,count)
Adds the count colors to the image's palette. Returns the index of
the first color added, or -1 if there is not enough space for count
colors.
-=item i_f_getcolors(im, index, colors, count)
+=item i_f_getcolors(im,index,colors,count)
Retrieves count colors from the image's palette starting from entry
index in the palette. Returns non-zero on success.
Returns the maximum number of colors that can fit in the image's
palette. Returns -1 if this is not a paletted image.
-=item i_f_findcolor(im, color, entry)
+=item i_f_findcolor(im,color,entry)
Searches the image's palette for the specified color, setting *entry
to the index and returning non-zero. Returns zero if the color is not
found.
-=item i_f_setcolors_t(im, index, colors, count)
+=item i_f_setcolors_t(im,index,colors,count)
Sets count colors starting from index in the image from the array
colors. The colors to be set must already have entries in the image's
Several functions have been written to simplify creating new image types.
-These tools are available by including imagei.h.
+These tools are available by including F<imagei.h>.
=head2 Floating point wrappers
=head2 Sample macros
-Imagei.h defines several macros for converting samples between
+C<imagei.h> defines several macros for converting samples between
different sizes.
-Each macro is of the form SampleI<size>ToI<size> where I<size> is one
+Each macro is of the form C<Sample>I<size>C<To>I<size> where I<size> is one
of 8, 16, or F (for floating-point samples).
=over
=back
+=head1 AUTHOR
+
+Tony Cook <tonyc@cpan.org>, Arnar M. Hrafnkelsson
+
=cut
projects / imager.git / blobdiff