[master] Reenabled png_set_dither() but renamed it to png_set_quantize() to

reflect more accurately what it actually does.  At the same time, renamed
the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros to
PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS.

1 files changed, 8 insertions, 7 deletions

diff --git a/example.c b/example.c
index b79d8413c..8d06182c0 100644
--- a/example.c
+++ b/example.c
@@ -160,7 +160,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
     * If you have enough memory to read in the entire image at once,
     * and you need to specify only transforms that can be controlled
     * with one of the PNG_TRANSFORM_* bits (this presently excludes
-    * dithering, filling, setting background, and doing gamma
+    * quantizing, filling, setting background, and doing gamma
     * adjustment), then you can read the entire image (including
     * pixels) into the info structure with this call:
     */
@@ -271,8 +271,8 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
          png_set_gamma(png_ptr, screen_gamma, 0.45455);
    }
 
-#ifdef PNG_READ_DITHER_SUPPORTED
-   /* Dither RGB files down to 8 bit palette or reduce palettes
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   /* Quantize RGB files down to 8 bit palette or reduce palettes
     * to the number of colors available on your screen.
     */
    if (color_type & PNG_COLOR_MASK_COLOR)
@@ -283,10 +283,11 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
       /* This reduces the image to the application supplied palette */
       if (/* We have our own palette */)
       {
-         /* An array of colors to which the image should be dithered */
+         /* An array of colors to which the image should be quantized */
          png_color std_color_cube[MAX_SCREEN_COLORS];
 
-         png_set_dither(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
+         /* Prior to libpng-1.4.2, this was png_set_dither(). */
+         png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
             MAX_SCREEN_COLORS, NULL, 0);
       }
       /* This reduces the image to the palette supplied in the file */
@@ -296,11 +297,11 @@ void read_png(FILE *fp, unsigned int sig_read)  /* File is already open */
 
          png_get_hIST(png_ptr, info_ptr, &histogram);
 
-         png_set_dither(png_ptr, palette, num_palette,
+         png_set_quantize(png_ptr, palette, num_palette,
                         max_screen_colors, histogram, 0);
       }
    }
-#endif /* PNG_READ_DITHER_SUPPORTED */
+#endif /* PNG_READ_QUANTIZE_SUPPORTED */
 
    /* Invert monochrome files to have 0 as white and 1 as black */
    png_set_invert_mono(png_ptr);