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Annotation of embedaddon/php/ext/gd/libgd/testac.c, revision 1.1.1.1

1.1       misho       1: 
                      2: #include <stdio.h>
                      3: #include "gd.h"
                      4: 
                      5: /* If palette is true, we convert from truecolor to palette at the end,
                      6:    to test gdImageTrueColorToPalette and see file size/
                      7:    quality tradeoffs. */
                      8: 
                      9: void testDrawing (
                     10:                   gdImagePtr im_in,
                     11:                   double scale,
                     12:                   int blending,
                     13:                   int palette,
                     14:                   char *filename);
                     15: 
                     16: int
                     17: main (int argc, char *argv[])
                     18: {
                     19:   /* Input and output files */
                     20:   FILE *in;
                     21:   FILE *out;
                     22: 
                     23:   /* Input image */
                     24:   gdImagePtr im_in = 0;
                     25: 
                     26:   /* Colors */
                     27:   int lightBlue;
                     28: 
                     29:   if (argc != 2)
                     30:     {
                     31:       fprintf (stderr, "Usage: testac filename.png\n");
                     32:       exit (1);
                     33:     }
                     34:   /* Load original PNG, which should contain alpha channel
                     35:      information. We will use it in two ways: preserving it
                     36:      literally, for use with compatible browsers, and
                     37:      compositing it ourselves against a background of our
                     38:      choosing (alpha blending). We'll change its size
                     39:      and try creating palette versions of it. */
                     40:   in = fopen (argv[1], "rb");
                     41:   if (!in)
                     42:     {
                     43:       fprintf (stderr, "Can't load %s.\n", argv[1]);
                     44:       exit (1);
                     45:     }
                     46:   else
                     47:     {
                     48:       im_in = gdImageCreateFromPng (in);
                     49:       fclose (in);
                     50:     }
                     51:   testDrawing (im_in, 1.0, 0, 0, "noblending-fullsize-truecolor.png");
                     52:   testDrawing (im_in, 1.0, 1, 0, "blending-fullsize-truecolor.png");
                     53:   testDrawing (im_in, 0.5, 0, 0, "noblending-halfsize-truecolor.png");
                     54:   testDrawing (im_in, 0.5, 1, 0, "blending-halfsize-truecolor.png");
                     55:   testDrawing (im_in, 2.0, 0, 0, "noblending-doublesize-truecolor.png");
                     56:   testDrawing (im_in, 2.0, 1, 0, "blending-doublesize-truecolor.png");
                     57:   testDrawing (im_in, 1.0, 0, 1, "noblending-fullsize-palette.png");
                     58:   testDrawing (im_in, 1.0, 1, 1, "blending-fullsize-palette.png");
                     59:   testDrawing (im_in, 0.5, 0, 1, "noblending-halfsize-palette.png");
                     60:   testDrawing (im_in, 0.5, 1, 1, "blending-halfsize-palette.png");
                     61:   testDrawing (im_in, 2.0, 0, 1, "noblending-doublesize-palette.png");
                     62:   testDrawing (im_in, 2.0, 1, 1, "blending-doublesize-palette.png");
                     63:   gdImageDestroy (im_in);
                     64:   return 0;
                     65: }
                     66: 
                     67: /* If palette is true, we convert from truecolor to palette at the end,
                     68:    to test gdImageTrueColorToPalette and see file size/
                     69:    quality tradeoffs. */
                     70: void
                     71: testDrawing (
                     72:              gdImagePtr im_in,
                     73:              double scale,
                     74:              int blending,
                     75:              int palette,
                     76:              char *filename)
                     77: {
                     78:   gdImagePtr im_out;
                     79:   FILE *out;
                     80:   /* Create output image. */
                     81:   im_out = gdImageCreateTrueColor ((int) (gdImageSX (im_in) * scale),
                     82:                                   (int) (gdImageSY (im_in) * scale));
                     83:   /*
                     84:      Request alpha blending. This causes future
                     85:      drawing operations to perform alpha channel blending
                     86:      with the background, resulting in an opaque image.
                     87:      Without this call, pixels in the foreground color are
                     88:      copied literally, *including* the alpha channel value,
                     89:      resulting in an output image which is potentially
                     90:      not opaque. This flag can be set and cleared as often
                     91:      as desired. */
                     92:   gdImageAlphaBlending (im_out, blending);
                     93: 
                     94:   /* Flood with light blue. */
                     95:   gdImageFill (im_out, (int) (gdImageSX (im_in) * scale / 2),
                     96:               (int) (gdImageSY (im_in) * scale / 2),
                     97:               gdTrueColor (192, 192, 255));
                     98:   /* Copy the source image. Alpha blending should result in
                     99:      compositing against red. With blending turned off, the
                    100:      browser or viewer will composite against its preferred
                    101:      background, or, if it does not support an alpha channel,
                    102:      we will see the original colors for the pixels that
                    103:      ought to be transparent or semitransparent. */
                    104:   gdImageCopyResampled (im_out, im_in,
                    105:                        0, 0,
                    106:                        0, 0,
                    107:        (int) (gdImageSX (im_in) * scale), (int) (gdImageSY (im_in) * scale),
                    108:                        gdImageSX (im_in), gdImageSY (im_in));
                    109:   /* Write PNG */
                    110:   out = fopen (filename, "wb");
                    111: 
                    112:   /* If this image is the result of alpha channel blending,
                    113:      it will not contain an interesting alpha channel itself.
                    114:      Save a little file size by not saving the alpha channel.
                    115:      Otherwise the file would typically be slightly larger. */
                    116:   gdImageSaveAlpha (im_out, !blending);
                    117: 
                    118:   /* If requested, convert from truecolor to palette. */
                    119:   if (palette)
                    120:     {
                    121:       /* Dithering, 256 colors. */
                    122:       gdImageTrueColorToPalette (im_out, 1, 256);
                    123:     }
                    124: 
                    125:   gdImagePng (im_out, out);
                    126:   fclose (out);
                    127: 
                    128:   gdImageDestroy (im_out);
                    129: }