1set_color_conversion(3) Allegro manual set_color_conversion(3)
2
6 set_color_conversion - Tells Allegro how to convert images during load‐
7 ing time.
8
10 #include <allegro.h>
11 void set_color_conversion(int mode);
14
16 Specifies how to convert images between the various color depths when
17 reading graphics from external bitmap files or datafiles. The mode is a
18 bitmask specifying which types of conversion are allowed. If the appro‐
19 priate bit is set, data will be converted into the current pixel format
20 (selected by calling the set_color_depth() function), otherwise it will
21 be left in the same format as the disk file, leaving you to convert it
22 manually before the graphic can be displayed. The default mode is total
23 conversion, so that all images will be loaded in the appropriate format
24 for the current video mode. Valid bit flags are:
25 COLORCONV_NONE // disable all format
27 // conversions
28 COLORCONV_8_TO_15 // expand 8-bit to 15-bit
29 COLORCONV_8_TO_16 // expand 8-bit to 16-bit
30 COLORCONV_8_TO_24 // expand 8-bit to 24-bit
31 COLORCONV_8_TO_32 // expand 8-bit to 32-bit
32 COLORCONV_15_TO_8 // reduce 15-bit to 8-bit
33 COLORCONV_15_TO_16 // expand 15-bit to 16-bit
34 COLORCONV_15_TO_24 // expand 15-bit to 24-bit
35 COLORCONV_15_TO_32 // expand 15-bit to 32-bit
36 COLORCONV_16_TO_8 // reduce 16-bit to 8-bit
37 COLORCONV_16_TO_15 // reduce 16-bit to 15-bit
38 COLORCONV_16_TO_24 // expand 16-bit to 24-bit
39 COLORCONV_16_TO_32 // expand 16-bit to 32-bit
40 COLORCONV_24_TO_8 // reduce 24-bit to 8-bit
41 COLORCONV_24_TO_15 // reduce 24-bit to 15-bit
42 COLORCONV_24_TO_16 // reduce 24-bit to 16-bit
43 COLORCONV_24_TO_32 // expand 24-bit to 32-bit
44 COLORCONV_32_TO_8 // reduce 32-bit RGB to 8-bit
45 COLORCONV_32_TO_15 // reduce 32-bit RGB to 15-bit
46 COLORCONV_32_TO_16 // reduce 32-bit RGB to 16-bit
47 COLORCONV_32_TO_24 // reduce 32-bit RGB to 24-bit
48 COLORCONV_32A_TO_8 // reduce 32-bit RGBA to 8-bit
49 COLORCONV_32A_TO_15 // reduce 32-bit RGBA to 15-bit
50 COLORCONV_32A_TO_16 // reduce 32-bit RGBA to 16-bit
51 COLORCONV_32A_TO_24 // reduce 32-bit RGBA to 24-bit
52 COLORCONV_DITHER_PAL // dither when reducing to 8-bit
53 COLORCONV_DITHER_HI // dither when reducing to
54 // hicolor
55 COLORCONV_KEEP_TRANS // keep original transparency
56 For convenience, the following macros can be used to select common com‐
58 binations of these flags:
59 COLORCONV_EXPAND_256 // expand 256-color to hi/truecolor
61 COLORCONV_REDUCE_TO_256 // reduce hi/truecolor to 256-color
62 COLORCONV_EXPAND_15_TO_16 // expand 15-bit hicolor to 16-bit
63 COLORCONV_REDUCE_16_TO_15 // reduce 16-bit hicolor to 15-bit
64 COLORCONV_EXPAND_HI_TO_TRUE // expand 15/16-bit to 24/32-bit
65 COLORCONV_REDUCE_TRUE_TO_HI // reduce 24/32-bit to 15/16-bit
66 COLORCONV_24_EQUALS_32 // convert between 24- and 32-bit
67 COLORCONV_TOTAL // everything to current format
68 COLORCONV_PARTIAL // convert 15 <-> 16-bit and
69 // 24 <-> 32-bit
70 COLORCONV_MOST // all but hi/truecolor <-> 256
71 COLORCONV_DITHER // dither during all color reductions
72 COLORCONV_KEEP_ALPHA // convert everything to current format
73 // unless it would lose alpha information
74 If you enable the COLORCONV_DITHER flag, dithering will be performed
76 whenever truecolor graphics are converted into a hicolor or paletted
77 format, including by the blit() function, and any automatic conversions
78 that take place while reading graphics from disk. This can produce much
79 better looking results, but is obviously slower than a direct conver‐
80 sion.
81 If you intend using converted bitmaps with functions like masked_blit()
83 or draw_sprite(), you should specify the COLORCONV_KEEP_TRANS flag. It
84 will ensure that the masked areas in the bitmap before and after the
85 conversion stay exactly the same, by mapping transparent colors to each
86 other and adjusting colors which would be converted to the transparent
87 color otherwise. It affects every blit() operation between distinct
88 pixel formats and every automatic conversion.
89
92 set_color_depth(3), load_bitmap(3), load_datafile(3),
93 fixup_datafile(3), makecol15_dither(3), get_color_conversion(3), exal‐
94 pha(3), exblend(3), exdata(3), exexedat(3), exlights(3), exxfade(3)
95Allegro version 4.2.3 set_color_conversion(3)