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-rw-r--r--Build/source/texk/dvipdfm-x/pngimage.c166
1 files changed, 129 insertions, 37 deletions
diff --git a/Build/source/texk/dvipdfm-x/pngimage.c b/Build/source/texk/dvipdfm-x/pngimage.c
index d4c33f11d13..694bb40e361 100644
--- a/Build/source/texk/dvipdfm-x/pngimage.c
+++ b/Build/source/texk/dvipdfm-x/pngimage.c
@@ -29,11 +29,10 @@
*
* All bitdepth less than 16 is supported.
* Supported color types are: PALETTE, RGB, GRAY, RGB_ALPHA, GRAY_ALPHA.
- * Supported ancillary chunks: tRNS, cHRM + gAMA, (sRGB), (iCCP)
+ * Supported ancillary chunks: tRNS, cHRM, gAMA, (sRGB), (iCCP)
*
- * gAMA support is available only when cHRM exists. cHRM support is not
- * tested well. CalRGB/CalGray colorspace is used for PNG images that
- * have cHRM chunk (but not sRGB).
+ * cHRM support is not tested well. CalRGB/CalGray colorspace is used for
+ * PNG images that have cHRM chunk.
*
* LIMITATIONS
*
@@ -82,18 +81,15 @@
/* ColorSpace */
static pdf_obj *create_cspace_Indexed (png_structp png_ptr, png_infop info_ptr);
-/* CIE-Based: CalRGB/CalGray
- *
- * We ignore gAMA if cHRM is not found.
- */
+/* CIE-Based: CalRGB/CalGray */
static pdf_obj *create_cspace_CalRGB (png_structp png_ptr, png_infop info_ptr);
static pdf_obj *create_cspace_CalGray (png_structp png_ptr, png_infop info_ptr);
static pdf_obj *make_param_Cal (png_byte color_type,
- double G,
- double xw, double yw,
- double xr, double yr,
- double xg, double yg,
- double xb, double yb);
+ double G,
+ double xw, double yw,
+ double xr, double yr,
+ double xg, double yg,
+ double xb, double yb);
/* sRGB:
*
@@ -124,17 +120,32 @@ static pdf_obj *create_ckey_mask (png_structp png_ptr, png_infop info_ptr);
* An object representing mask itself is returned.
*/
static pdf_obj *create_soft_mask (png_structp png_ptr, png_infop info_ptr,
- png_bytep image_data_ptr,
- png_uint_32 width, png_uint_32 height);
+ png_bytep image_data_ptr,
+ png_uint_32 width, png_uint_32 height);
static pdf_obj *strip_soft_mask (png_structp png_ptr, png_infop info_ptr,
- png_bytep image_data_ptr,
- png_uint_32p rowbytes_ptr,
- png_uint_32 width, png_uint_32 height);
+ png_bytep image_data_ptr,
+ png_uint_32p rowbytes_ptr,
+ png_uint_32 width, png_uint_32 height);
+
+/* Gamma correction
+ *
+ * NOTE: It fails reproducing "Browser Gamma-Consistency Test"
+ *
+ * http://www.libpng.org/pub/png/colorcube/gamma-consistency-test.html
+ *
+ * correctly.
+ */
+static void gamma_correct_bpc8 (double gamma, png_bytep image_data_ptr,
+ png_uint_32 height, png_uint_32 rowbytes);
+static void gamma_correct_bpc4 (double gamma, png_bytep image_data_ptr,
+ png_uint_32 height, png_uint_32 rowbytes);
+static void gamma_correct_bpc2 (double gamma, png_bytep image_data_ptr,
+ png_uint_32 height, png_uint_32 rowbytes);
/* Read image body */
static void read_image_data (png_structp png_ptr,
- png_bytep dest_ptr,
- png_uint_32 height, png_uint_32 rowbytes);
+ png_bytep dest_ptr,
+ png_uint_32 height, png_uint_32 rowbytes);
int
check_for_png (FILE *png_file)
@@ -277,16 +288,12 @@ png_include_image (pdf_ximage *ximage, FILE *png_file)
switch (trans_type) {
case PDF_TRANS_TYPE_BINARY:
- if (color_type != PNG_COLOR_TYPE_RGB)
- ERROR("Unexpected error in png_include_image().");
mask = create_ckey_mask(png_ptr, png_info_ptr);
break;
/* rowbytes changes 4 to 3 at here */
case PDF_TRANS_TYPE_ALPHA:
- if (color_type != PNG_COLOR_TYPE_RGB_ALPHA)
- ERROR("Unexpected error in png_include_image().");
mask = strip_soft_mask(png_ptr, png_info_ptr,
- stream_data_ptr, &rowbytes, width, height);
+ stream_data_ptr, &rowbytes, width, height);
break;
default:
mask = NULL;
@@ -309,15 +316,11 @@ png_include_image (pdf_ximage *ximage, FILE *png_file)
switch (trans_type) {
case PDF_TRANS_TYPE_BINARY:
- if (color_type != PNG_COLOR_TYPE_GRAY)
- ERROR("Unexpected error in png_include_image().");
mask = create_ckey_mask(png_ptr, png_info_ptr);
break;
case PDF_TRANS_TYPE_ALPHA:
- if (color_type != PNG_COLOR_TYPE_GRAY_ALPHA)
- ERROR("Unexpected error in png_include_image().");
mask = strip_soft_mask(png_ptr, png_info_ptr,
- stream_data_ptr, &rowbytes, width, height);
+ stream_data_ptr, &rowbytes, width, height);
break;
default:
mask = NULL;
@@ -330,6 +333,26 @@ png_include_image (pdf_ximage *ximage, FILE *png_file)
}
pdf_add_dict(stream_dict, pdf_new_name("ColorSpace"), colorspace);
+ /* Gamma correction for DeviceRGB and DeviceGray
+ * We apply gamma correction here when gAMA chunk exists but NOT cHRM chunk.
+ */
+ if ( color_type != PNG_COLOR_TYPE_PALETTE &&
+ png_get_valid(png_ptr, png_info_ptr, PNG_INFO_gAMA) &&
+ !png_get_valid(png_ptr, png_info_ptr, PNG_INFO_cHRM)) {
+ double G = 1.0;
+ png_get_gAMA(png_ptr, png_info_ptr, &G);
+ if (G < 1.0e-5) {
+ WARN("%s: Unexpected Gamma value: 1.0 / %g", PNG_DEBUG_STR, G);
+ G = 1.0;
+ }
+ if (bpc == 8)
+ gamma_correct_bpc8(1.0 / G, stream_data_ptr, height, rowbytes);
+ else if (bpc == 4)
+ gamma_correct_bpc4(1.0 / G, stream_data_ptr, height, rowbytes);
+ else if (bpc == 2)
+ gamma_correct_bpc2(1.0 / G, stream_data_ptr, height, rowbytes);
+ }
+
pdf_add_stream(stream, stream_data_ptr, rowbytes*height);
RELEASE(stream_data_ptr);
@@ -340,7 +363,7 @@ png_include_image (pdf_ximage *ximage, FILE *png_file)
pdf_add_dict(stream_dict, pdf_new_name("SMask"), pdf_ref_obj(mask));
pdf_release_obj(mask);
} else {
- WARN("%s: You found a bug in pngimage.c.", PNG_DEBUG_STR);
+ WARN("%s: Unknown transparency type...???", PNG_DEBUG_STR);
pdf_release_obj(mask);
}
}
@@ -671,7 +694,7 @@ create_cspace_CalRGB (png_structp png_ptr, png_infop info_ptr)
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_gAMA) &&
png_get_gAMA (png_ptr, info_ptr, &G)) {
if (G < 1.0e-2) {
- WARN("%s: Unusual Gamma value: %g", PNG_DEBUG_STR, G);
+ WARN("%s: Unusual Gamma value: 1.0 / %g", PNG_DEBUG_STR, G);
return NULL;
}
G = 1.0 / G; /* Gamma is inverted. */
@@ -712,7 +735,7 @@ create_cspace_CalGray (png_structp png_ptr, png_infop info_ptr)
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_gAMA) &&
png_get_gAMA (png_ptr, info_ptr, &G)) {
if (G < 1.0e-2) {
- WARN("%s: Unusual Gamma value: %g", PNG_DEBUG_STR, G);
+ WARN("%s: Unusual Gamma value: 1.0 / %g", PNG_DEBUG_STR, G);
return NULL;
}
G = 1.0 / G; /* Gamma is inverted. */
@@ -782,7 +805,7 @@ make_param_Cal (png_byte color_type,
}
if (G < 1.0e-2) {
- WARN("Unusual Gamma specified: %g", G);
+ WARN("Unusual Gamma specified: 1.0 / %g", G);
return NULL;
}
@@ -873,6 +896,18 @@ create_cspace_Indexed (png_structp png_ptr, png_infop info_ptr)
data_ptr[3*i+1] = plte[i].green;
data_ptr[3*i+2] = plte[i].blue;
}
+ /* Gamma correction */
+ if ( png_get_valid(png_ptr, info_ptr, PNG_INFO_gAMA) &&
+ !png_get_valid(png_ptr, info_ptr, PNG_INFO_cHRM) ) {
+ double G = 1.0;
+ png_get_gAMA(png_ptr, info_ptr, &G);
+ if (G < 1.0e-5) {
+ WARN("%s: Ignoring unusual Gamma value: 1.0 / %g", PNG_DEBUG_STR, G);
+ G = 1.0;
+ }
+ if (G != 1.0)
+ gamma_correct_bpc8(1.0 / G, (png_bytep) data_ptr, 1, num_plte*3);
+ }
lookup = pdf_new_string(data_ptr, num_plte*3);
RELEASE(data_ptr);
pdf_add_array(colorspace, lookup);
@@ -909,10 +944,10 @@ create_ckey_mask (png_structp png_ptr, png_infop info_ptr)
case PNG_COLOR_TYPE_PALETTE:
for (i = 0; i < num_trans; i++) {
if (trans[i] == 0x00) {
- pdf_add_array(colorkeys, pdf_new_number(i));
- pdf_add_array(colorkeys, pdf_new_number(i));
+ pdf_add_array(colorkeys, pdf_new_number(i));
+ pdf_add_array(colorkeys, pdf_new_number(i));
} else if (trans[i] != 0xff) {
- WARN("%s: You found a bug in pngimage.c.", PNG_DEBUG_STR);
+ WARN("%s: You found a bug in pngimage.c.", PNG_DEBUG_STR);
}
}
break;
@@ -1052,6 +1087,63 @@ strip_soft_mask (png_structp png_ptr, png_infop info_ptr,
return smask;
}
+/* Gamma correction stuff
+ * bpc4 and bpc2 is untested.
+ */
+static void
+gamma_correct_bpc8 (double G, png_bytep stream_data_ptr,
+ png_uint_32 height, png_uint_32 rowbytes)
+{
+ png_uint_32 i, j;
+
+ for (i = 0; i < height; i++) {
+ for (j = 0; j < rowbytes; j++) {
+ stream_data_ptr[i * rowbytes + j] =
+ (png_byte) (255.0 * pow(stream_data_ptr[i * rowbytes + j] / 255.0, G) + 0.5);
+ }
+ }
+}
+
+static void
+gamma_correct_bpc4 (double G, png_bytep stream_data_ptr,
+ png_uint_32 height, png_uint_32 rowbytes)
+{
+ png_uint_32 i, j;
+
+ for (i = 0; i < height; i++) {
+ for (j = 0; j < rowbytes; j++) {
+ png_byte v1, v2;
+ v1 = (stream_data_ptr[i * rowbytes + j] >> 4) & 0x0f;
+ v2 = stream_data_ptr[i * rowbytes + j] & 0x0f;
+ v1 = (png_byte) (15.0 * pow(v1 / 15.0, G) + 0.5);
+ v2 = (png_byte) (15.0 * pow(v2 / 15.0, G) + 0.5);
+ stream_data_ptr[i * rowbytes + j] = (v1 << 4) + v2;
+ }
+ }
+}
+
+static void
+gamma_correct_bpc2 (double G, png_bytep stream_data_ptr,
+ png_uint_32 height, png_uint_32 rowbytes)
+{
+ png_uint_32 i, j;
+
+ for (i = 0; i < height; i++) {
+ for (j = 0; j < rowbytes; j++) {
+ png_byte v1, v2, v3, v4;
+ v1 = (stream_data_ptr[i * rowbytes + j] >> 6) & 0x03;
+ v2 = (stream_data_ptr[i * rowbytes + j] >> 4) & 0x03;
+ v3 = (stream_data_ptr[i * rowbytes + j] >> 2) & 0x03;
+ v4 = stream_data_ptr[i * rowbytes + j] & 0x03;
+ v1 = (png_byte) (3.0 * pow(v1 / 3.0, G) + 0.5);
+ v2 = (png_byte) (3.0 * pow(v2 / 3.0, G) + 0.5);
+ v3 = (png_byte) (3.0 * pow(v3 / 3.0, G) + 0.5);
+ v4 = (png_byte) (3.0 * pow(v4 / 3.0, G) + 0.5);
+ stream_data_ptr[i * rowbytes + j] = (v1 << 6) + (v2 << 4) + (v3 << 2) + v4;
+ }
+ }
+}
+
static void
read_image_data (png_structp png_ptr, png_bytep dest_ptr,
png_uint_32 height, png_uint_32 rowbytes)
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-20 11:22:11 +0000