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png loader now pays head to images "quality" tag, just like the jpeg loader. 

Now, the png lib takes values 1-9 for compression. I decided to standardise
loaders on a 1-100 quality value, and do some sums in the loader to convert
to 1-9 compression. That was you can set quality and not care what file
format is used. Sound reasonable?


SVN revision: 3772
This commit is contained in:
Tom Gilbert 2000-10-29 00:31:37 +00:00
parent ed96b0c6ff
commit d1227691a0
1 changed files with 15 additions and 0 deletions
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15
loaders/loader_png.c
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@ -277,6 +277,8 @@ save (ImlibImage *im, ImlibProgressFunction progress,
png_color_8 sig_bit;
int pl = 0;
char pper = 0;
ImlibImageTag *tag;
int quality = 75, compression;
f = fopen(im->file, "wb");
if (!f)
@ -325,6 +327,19 @@ save (ImlibImage *im, ImlibProgressFunction progress,
sig_bit.blue = 8;
sig_bit.alpha = 8;
png_set_sBIT(png_ptr, info_ptr, &sig_bit);
/* compression */
tag = __imlib_GetTag(im, "quality");
if (tag)
quality = tag->val;
if (quality < 10)
quality = 10;
if (quality > 99)
quality = 99;
/* translate to png-relevant value */
quality = quality / 10;
compression = 10 - quality;
/* should be 1-9 now */
png_set_compression_level(png_ptr, compression);
png_write_info(png_ptr, info_ptr);
png_set_shift(png_ptr, &sig_bit);
png_set_packing(png_ptr);