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PNG re-work: paletted file writes

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commit 21c6936be4b83c217886fbf2a43c6d40bb645efa 1 parent 8108982
@tonycoz authored
Showing with 298 additions and 14 deletions.
  1. +198 −12 PNG/impng.c
  2. +100 −2 PNG/t/10png.t
View
210 PNG/impng.c
@@ -1,5 +1,6 @@
#include "impng.h"
#include "png.h"
+#include <stdlib.h>
/* this is a way to get number of channels from color space
* Color code to channel number */
@@ -23,6 +24,13 @@ read_bilevel(png_structp png_ptr, png_infop info_ptr, i_img_dim width, i_img_dim
static int
write_direct8(png_structp png_ptr, png_infop info_ptr, i_img *im);
+static int
+write_paletted(png_structp png_ptr, png_infop info_ptr, i_img *im, int bits);
+
+static void
+pack_to_bits(unsigned char *dest, const unsigned char *src, size_t count,
+ int bits);
+
unsigned
i_png_lib_version(void) {
return png_access_version_number();
@@ -81,6 +89,7 @@ i_writepng_wiol(i_img *im, io_glue *ig) {
int aspect_only, have_res;
unsigned char *data;
unsigned char * volatile vdata = NULL;
+ int bits;
mm_log((1,"i_writepng(im %p ,ig %p)\n", im, ig));
@@ -111,13 +120,39 @@ i_writepng_wiol(i_img *im, io_glue *ig) {
channels=im->channels;
- if (channels > 2) { cspace = PNG_COLOR_TYPE_RGB; channels-=3; }
- else { cspace=PNG_COLOR_TYPE_GRAY; channels--; }
-
- if (channels) cspace|=PNG_COLOR_MASK_ALPHA;
- mm_log((1,"cspace=%d\n",cspace));
+ if (im->type == i_palette_type) {
+ int colors = i_colorcount(im);
+
+ cspace = PNG_COLOR_TYPE_PALETTE;
+ bits = 1;
+ while ((1 << bits) < colors) {
+ bits += bits;
+ }
+ mm_log((1, "paletted output\n"));
+ }
+ else {
+ switch (channels) {
+ case 1:
+ cspace = PNG_COLOR_TYPE_GRAY;
+ break;
+ case 2:
+ cspace = PNG_COLOR_TYPE_GRAY_ALPHA;
+ break;
+ case 3:
+ cspace = PNG_COLOR_TYPE_RGB;
+ break;
+ case 4:
+ cspace = PNG_COLOR_TYPE_RGB_ALPHA;
+ break;
+ default:
+ fprintf(stderr, "Internal error, channels = %d\n", channels);
+ abort();
+ }
+ bits = 8;
+ mm_log((1, "direct output\n"));
+ }
- channels = im->channels;
+ mm_log((1,"cspace=%d, bits=%d\n",cspace, bits));
/* Create and initialize the png_struct with the desired error handler
* functions. If you want to use the default stderr and longjump method,
@@ -167,8 +202,10 @@ i_writepng_wiol(i_img *im, io_glue *ig) {
*/
png_set_user_limits(png_ptr, width, height);
- png_set_IHDR(png_ptr, info_ptr, width, height, 8, cspace,
+ mm_log((1, ">png_set_IHDR\n"));
+ png_set_IHDR(png_ptr, info_ptr, width, height, bits, cspace,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+ mm_log((1, "<png_set_IHDR\n"));
have_res = 1;
if (i_tags_get_float(&im->tags, "i_xres", 0, &xres)) {
@@ -192,11 +229,17 @@ i_writepng_wiol(i_img *im, io_glue *ig) {
aspect_only ? PNG_RESOLUTION_UNKNOWN : PNG_RESOLUTION_METER);
}
- png_write_info(png_ptr, info_ptr);
-
- if (!write_direct8(png_ptr, info_ptr, im)) {
- png_destroy_write_struct(&png_ptr, &info_ptr);
- return 0;
+ if (im->type == i_palette_type) {
+ if (!write_paletted(png_ptr, info_ptr, im, bits)) {
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ return 0;
+ }
+ }
+ else {
+ if (!write_direct8(png_ptr, info_ptr, im)) {
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ return 0;
+ }
}
png_write_end(png_ptr, info_ptr);
@@ -733,6 +776,8 @@ write_direct8(png_structp png_ptr, png_infop info_ptr, i_img *im) {
return 0;
}
+ png_write_info(png_ptr, info_ptr);
+
vdata = data = mymalloc(im->xsize * im->channels);
for (y = 0; y < im->ysize; y++) {
i_gsamp(im, 0, im->xsize, y, data, NULL, im->channels);
@@ -743,6 +788,147 @@ write_direct8(png_structp png_ptr, png_infop info_ptr, i_img *im) {
return 1;
}
+static int
+write_paletted(png_structp png_ptr, png_infop info_ptr, i_img *im, int bits) {
+ unsigned char *data, *volatile vdata = NULL;
+ i_img_dim y;
+ unsigned char pal_map[256];
+ png_color pcolors[256];
+ i_color colors[256];
+ int count = i_colorcount(im);
+ int i;
+
+ if (setjmp(png_jmpbuf(png_ptr))) {
+ if (vdata)
+ myfree(vdata);
+
+ return 0;
+ }
+
+ i_getcolors(im, 0, colors, count);
+ if (im->channels < 3) {
+ /* convert the greyscale palette to color */
+ int i;
+ for (i = 0; i < count; ++i) {
+ i_color *c = colors + i;
+ c->channel[3] = c->channel[1];
+ c->channel[2] = c->channel[1] = c->channel[0];
+ }
+ }
+
+ if (i_img_has_alpha(im)) {
+ int i;
+ int bottom_index = 0, top_index = count-1;
+
+ /* fill out the palette map */
+ for (i = 0; i < count; ++i)
+ pal_map[i] = i;
+
+ /* the PNG spec suggests sorting the palette by alpha, but that's
+ unnecessary - all we want to do is move the opaque entries to
+ the end */
+ while (bottom_index < top_index) {
+ if (colors[bottom_index].rgba.a == 255) {
+ pal_map[bottom_index] = top_index;
+ pal_map[top_index--] = bottom_index;
+ }
+ ++bottom_index;
+ }
+ }
+
+ for (i = 0; i < count; ++i) {
+ int srci = i_img_has_alpha(im) ? pal_map[i] : i;
+
+ pcolors[i].red = colors[srci].rgb.r;
+ pcolors[i].green = colors[srci].rgb.g;
+ pcolors[i].blue = colors[srci].rgb.b;
+ }
+
+ png_set_PLTE(png_ptr, info_ptr, pcolors, count);
+
+ if (i_img_has_alpha(im)) {
+ unsigned char trans[256];
+ int i;
+
+ for (i = 0; i < count && colors[pal_map[i]].rgba.a != 255; ++i) {
+ trans[i] = colors[pal_map[i]].rgba.a;
+ }
+ png_set_tRNS(png_ptr, info_ptr, trans, i, NULL);
+ }
+
+ png_write_info(png_ptr, info_ptr);
+
+ png_set_packing(png_ptr);
+
+ vdata = data = mymalloc(im->xsize);
+ for (y = 0; y < im->ysize; y++) {
+ i_gpal(im, 0, im->xsize, y, data);
+ if (i_img_has_alpha(im)) {
+ i_img_dim x;
+ for (x = 0; x < im->xsize; ++x)
+ data[x] = pal_map[data[x]];
+ }
+ png_write_row(png_ptr, (png_bytep)data);
+ }
+ myfree(data);
+
+ return 1;
+}
+
+#if 0
+/* the source size is required to be rounded up to a number of samples
+ per byte bounday */
+static void
+pack_to_bits(unsigned char *dest, const unsigned char *src, size_t count,
+ int bits) {
+ ptr_diff_t out_count;
+ switch (bits) {
+ case 1:
+ out_count = (count + 7) / 8;
+ while (out_count > 0) {
+ unsigned mask = 0x80;
+ unsigned out = 0;
+ while (mask) {
+ if (*src++)
+ out |= mask;
+ mask >>= 1;
+ }
+ *dest++ = out;
+ --out_count;
+ }
+ break;
+
+ case 2:
+ out_count = (count + 3) / 4;
+ while (out_count > 0) {
+ int shift = 6;
+ unsigned out = 0;
+ while (shift >= 0) {
+ out |= *src << shift;
+ ++src;
+ shift -= 2;
+ }
+ *dest++ = out;
+ --out_count;
+ }
+ break;
+
+ case 4:
+ out_count = (count + 1) / 2;
+ while (out_count > 0) {
+ *dest++ = (src[0] << 4) | src[1];
+ src += 2;
+ --out_count;
+ }
+ break
+
+ case 8:
+ break;
+ }
+}
+
+#endif
+
static void
read_warn_handler(png_structp png_ptr, png_const_charp msg) {
i_png_read_statep rs = (i_png_read_statep)png_get_error_ptr(png_ptr);
View
102 PNG/t/10png.t
@@ -10,7 +10,7 @@ my $debug_writes = 1;
init_log("testout/t102png.log",1);
-plan tests => 151;
+plan tests => 187;
# this loads Imager::File::PNG too
ok($Imager::formats{"png"}, "must have png format");
@@ -35,7 +35,8 @@ Imager::i_tags_add($img, "i_yres", 0, undef, 200);
open(FH,">testout/t102.png") || die "cannot open testout/t102.png for writing\n";
binmode(FH);
my $IO = Imager::io_new_fd(fileno(FH));
-ok(Imager::File::PNG::i_writepng_wiol($img, $IO), "write");
+ok(Imager::File::PNG::i_writepng_wiol($img, $IO), "write")
+ or diag(Imager->_error_as_msg());
close(FH);
open(FH,"testout/t102.png") || die "cannot open testout/t102.png\n";
@@ -423,6 +424,102 @@ SKIP:
}
}
+{
+ my $pim = Imager->new(xsize => 5, ysize => 2, channels => 3, type => "paletted");
+ ok($pim, "make a 3 channel paletted image");
+ ok($pim->addcolors(colors => [ qw(#000 #FFF #F00 #0F0 #00f) ]),
+ "add some colors");
+ is($pim->setscanline(y => 0, type => "index",
+ pixels => [ 0, 1, 2, 4, 3 ]), 5, "set some pixels");
+ is($pim->setscanline(y => 1, type => "index",
+ pixels => [ 4, 1, 0, 4, 2 ]), 5, "set some more pixels");
+ ok($pim->write(file => "testout/pal3.png"),
+ "write to testout/pal3.png")
+ or diag("Cannot save testout/pal3.png: ".$pim->errstr);
+ my $in = Imager->new(file => "testout/pal3.png");
+ ok($in, "read it back in")
+ or diag("Cann't read pal3.png back: " . Imager->errstr);
+ is_image($pim, $in, "check it matches");
+ is($in->type, "paletted", "make sure the result is paletted");
+ is($in->tags(name => "png_bits"), 4, "4 bit representation");
+}
+
+{
+ # make sure the code that pushes maxed alpha to the end doesn't break
+ my $pim = Imager->new(xsize => 8, ysize => 2, channels => 4, type => "paletted");
+ ok($pim, "make a 4 channel paletted image");
+ ok($pim->addcolors
+ (colors => [ NC(255, 255, 0, 128), qw(#000 #FFF #F00 #0F0 #00f),
+ NC(0, 0, 0, 0), NC(255, 0, 128, 64) ]),
+ "add some colors");
+ is($pim->setscanline(y => 0, type => "index",
+ pixels => [ 5, 0, 1, 7, 2, 4, 6, 3 ]), 8,
+ "set some pixels");
+ is($pim->setscanline(y => 1, type => "index",
+ pixels => [ 7, 4, 6, 1, 0, 4, 2, 5 ]), 8,
+ "set some more pixels");
+ ok($pim->write(file => "testout/pal4.png"),
+ "write to testout/pal4.png")
+ or diag("Cannot save testout/pal4.png: ".$pim->errstr);
+ my $in = Imager->new(file => "testout/pal4.png");
+ ok($in, "read it back in")
+ or diag("Cann't read pal4.png back: " . Imager->errstr);
+ is_image($pim, $in, "check it matches");
+ is($in->type, "paletted", "make sure the result is paletted");
+ is($in->tags(name => "png_bits"), 4, "4 bit representation");
+}
+
+{
+ my $pim = Imager->new(xsize => 8, ysize => 2, channels => 1, type => "paletted");
+ ok($pim, "make a 1 channel paletted image");
+ ok($pim->addcolors(colors => [ map NC($_, 0, 0), 0, 7, 127, 255 ]),
+ "add some colors^Wgreys");
+ is($pim->setscanline(y => 0, type => "index",
+ pixels => [ 0, 2, 1, 3, 2, 1, 0, 3 ]), 8,
+ "set some pixels");
+ is($pim->setscanline(y => 1, type => "index",
+ pixels => [ 3, 0, 2, 1, 0, 0, 2, 3 ]), 8,
+ "set some more pixels");
+ ok($pim->write(file => "testout/pal1.png"),
+ "write to testout/pal1.png")
+ or diag("Cannot save testout/pal1.png: ".$pim->errstr);
+ my $in = Imager->new(file => "testout/pal1.png");
+ ok($in, "read it back in")
+ or diag("Cann't read pal1.png back: " . Imager->errstr);
+ # PNG doesn't have a paletted greyscale type, so it's written as
+ # paletted color, convert our source image for the comparison
+ my $cmpim = $pim->convert(preset => "rgb");
+ is_image($in, $cmpim, "check it matches");
+ is($in->type, "paletted", "make sure the result is paletted");
+ is($in->tags(name => "png_bits"), 2, "2 bit representation");
+}
+
+{
+ my $pim = Imager->new(xsize => 8, ysize => 2, channels => 2, type => "paletted");
+ ok($pim, "make a 2 channel paletted image");
+ ok($pim->addcolors(colors => [ NC(0, 255, 0), NC(128, 255, 0), NC(255, 255, 0), NC(128, 128, 0) ]),
+ "add some colors^Wgreys")
+ or diag("adding colors: " . $pim->errstr);
+ is($pim->setscanline(y => 0, type => "index",
+ pixels => [ 0, 2, 1, 3, 2, 1, 0, 3 ]), 8,
+ "set some pixels");
+ is($pim->setscanline(y => 1, type => "index",
+ pixels => [ 3, 0, 2, 1, 0, 0, 2, 3 ]), 8,
+ "set some more pixels");
+ ok($pim->write(file => "testout/pal2.png"),
+ "write to testout/pal2.png")
+ or diag("Cannot save testout/pal2.png: ".$pim->errstr);
+ my $in = Imager->new(file => "testout/pal2.png");
+ ok($in, "read it back in")
+ or diag("Cann't read pal1.png back: " . Imager->errstr);
+ # PNG doesn't have a paletted greyscale type, so it's written as
+ # paletted color, convert our source image for the comparison
+ my $cmpim = $pim->convert(preset => "rgb");
+ is_image($in, $cmpim, "check it matches");
+ is($in->type, "paletted", "make sure the result is paletted");
+ is($in->tags(name => "png_bits"), 2, "2 bit representation");
+}
+
sub limited_write {
my ($limit) = @_;
@@ -441,3 +538,4 @@ sub limited_write {
}
};
}
+
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