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Imported from libpng-0.98.tar

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This commit is contained in:
Glenn Randers-Pehrson
1998-01-16 22:06:18 -06:00
parent 2687fcc7b5
commit c4a2ae6cac
26 changed files with 687 additions and 240 deletions
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16
example.c
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@@ -190,19 +190,22 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
/* Some suggestions as to how to get a screen gamma value */
/* Note that screen gamma is (display_gamma/viewing_gamma)
if (/* We have a user-defined screen gamma value */)
{
screen_gamma = user-defined screen_gamma;
}
/* This is one way that applications share the same screen gamma value */
else if ((gamma_str = getenv("DISPLAY_GAMMA")) != NULL)
else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
{
screen_gamma = atof(gamma_str);
}
/* If we don't have another value */
else
{
screen_gamma = 2.2; /* A good guess for PC monitors */
screen_gamma = 2.2; /* A good guess for a PC monitors in a brightly
lit room */
screen_gamma = 1.7 or 1.0; /* A good guess for Mac systems */
}
@@ -211,13 +214,16 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
* by the user at run time by the user. It is strongly suggested that
* your application support gamma correction.
*/
if (png_get_sRGB(png_ptr, info_ptr, &srgb_intent)
png_set_sRGB(png_ptr, srgb_intent, 0);
int intent;
if (png_get_sRGB(png_ptr, info_ptr, &intent)
png_set_sRGB(png_ptr, intent, 0);
else
if (png_get_gAMA(png_ptr, info_ptr, &image_gamma)
png_set_gamma(png_ptr, screen_gamma, image_gamma);
else
png_set_gamma(png_ptr, screen_gamma, 0.45);
png_set_gamma(png_ptr, screen_gamma, 0.51);
/* Dither RGB files down to 8 bit palette or reduce palettes
* to the number of colors available on your screen.