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Merge pull request #1678 from randy408/spng-fix 

Revise spngloader
This commit is contained in:
John Cupitt 2020-06-11 11:38:26 +01:00 committed by GitHub
parent ce63fc1145 2457e6768a
commit 49b35f708f
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 60 additions and 46 deletions
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106
libvips/foreign/spngload.c
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@ -315,50 +315,23 @@ vips_foreign_load_png_header( VipsForeignLoad *load )
png->ihdr.interlace_method );
*/
/* Just convert to host-endian if nothing else applies.
*/
png->fmt = SPNG_FMT_PNG;
switch( png->ihdr.color_type ) {
case SPNG_COLOR_TYPE_GRAYSCALE:
case SPNG_COLOR_TYPE_GRAYSCALE_ALPHA:
png->bands = 1;
png->interpretation = VIPS_INTERPRETATION_B_W;
png->fmt = SPNG_FMT_PNG;
if( !spng_get_trns( png->ctx, &trns ) ) {
png->bands += 1;
/* Expand 1/2/4 bit images to 8 bit.
*/
if( png->ihdr.bit_depth < 8 )
png->fmt = SPNG_FMT_GA8;
}
else {
if( png->ihdr.bit_depth < 8 )
png->fmt = SPNG_FMT_G8;
}
case SPNG_COLOR_TYPE_INDEXED:
bands = 3;
break;
case SPNG_COLOR_TYPE_TRUECOLOR:
case SPNG_COLOR_TYPE_TRUECOLOR_ALPHA:
png->bands = 3;
png->interpretation = VIPS_INTERPRETATION_sRGB;
png->fmt = SPNG_FMT_PNG;
if( !spng_get_trns( png->ctx, &trns ) )
png->bands += 1;
case SPNG_COLOR_TYPE_GRAYSCALE_ALPHA:
case SPNG_COLOR_TYPE_GRAYSCALE:
bands = 1;
break;
case SPNG_COLOR_TYPE_INDEXED:
png->bands = 3;
png->interpretation = VIPS_INTERPRETATION_sRGB;
/* Expand indexed images to RGB8.
*/
if( !spng_get_trns( png->ctx, &trns ) ) {
png->bands += 1;
png->fmt = SPNG_FMT_RGBA8;
}
else
png->fmt = SPNG_FMT_RGB8;
case SPNG_COLOR_TYPE_RGB:
case SPNG_COLOR_TYPE_RGB_ALPHA:
bands = 3;
break;
default:
@ -366,15 +339,56 @@ vips_foreign_load_png_header( VipsForeignLoad *load )
return( -1 );
}
if( png->ihdr.bit_depth == 16 ) {
png->format = VIPS_FORMAT_USHORT;
if( png->interpretation == VIPS_INTERPRETATION_B_W )
png->interpretation = VIPS_INTERPRETATION_GREY16;
if( png->interpretation == VIPS_INTERPRETATION_sRGB )
png->interpretation = VIPS_INTERPRETATION_RGB16;
if( bit_depth > 8 ) {
if( bands < 3 )
interpretation = VIPS_INTERPRETATION_GREY16;
else
interpretation = VIPS_INTERPRETATION_RGB16;
}
else {
if( bands < 3 )
interpretation = VIPS_INTERPRETATION_B_W;
else
interpretation = VIPS_INTERPRETATION_sRGB;
}
/* Expand palette images.
*/
if( png->ihdr.color_type == SPNG_COLOR_TYPE_INDEXED )
png->fmt = SPNG_FMT_RGB8;
/* Expand <8 bit images to full bytes.
*/
if( png->ihdr.color_type == SPNG_COLOR_TYPE_GRAYSCALE &&
png->ihdr.bit_depth < 8 )
png->fmt = SPNG_FMT_G8;
/* Expand transparency.
*/
if( !spng_get_trns( png->ctx, &trns ) ) {
bands += 1;
if( png->ihdr.color_type == SPNG_COLOR_TYPE_TRUECOLOR ) {
if( png->ihdr.bit_depth == 16 )
png->fmt = SPNG_FMT_RGBA16;
else
png->fmt = SPNG_FMT_RGBA8;
}
else if( png->ihdr.color_type == SPNG_COLOR_TYPE_INDEXED )
png->fmt = SPNG_FMT_RGBA8;
else if( png->ihdr.color_type == SPNG_COLOR_TYPE_GRAYSCALE ) {
if( png->ihdr.bit_depth == 16 )
png->fmt = SPNG_FMT_GA16;
else
png->fmt = SPNG_FMT_GA8;
}
}
else if( png->ihdr.color_type == SPNG_COLOR_TYPE_GRAYSCALE_ALPHA ||
png->ihdr.color_type == SPNG_COLOR_TYPE_TRUECOLOR_ALPHA ) {
/* Some images have their own alpha channel,
* not just a transparent color.
*/
bands += 1;
}
else
png->format = VIPS_FORMAT_UCHAR;
vips_source_minimise( png->source );