1 /*
2 Copyright 2010 Google Inc.
3
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15 */
16
17
18 #ifndef GrColor_DEFINED
19 #define GrColor_DEFINED
20
21 #include "GrTypes.h"
22
23 /**
24 * GrColor is 4 bytes for R, G, B, A, in a compile-time specific order. The
25 * components are stored premultiplied.
26 */
27 typedef uint32_t GrColor;
28
29 // indices for address a GrColor as an array of bytes
30
31 #define GrColor_INDEX_R 0
32 #define GrColor_INDEX_G 1
33 #define GrColor_INDEX_B 2
34 #define GrColor_INDEX_A 3
35
36 // shfit amount to assign a component to a GrColor int
37
38 #define GrColor_SHIFT_R 0
39 #define GrColor_SHIFT_G 8
40 #define GrColor_SHIFT_B 16
41 #define GrColor_SHIFT_A 24
42
43 /**
44 * Pack 4 components (RGBA) into a GrColor int
45 */
GrColorPackRGBA(unsigned r,unsigned g,unsigned b,unsigned a)46 static inline GrColor GrColorPackRGBA(unsigned r, unsigned g,
47 unsigned b, unsigned a) {
48 GrAssert((uint8_t)r == r);
49 GrAssert((uint8_t)g == g);
50 GrAssert((uint8_t)b == b);
51 GrAssert((uint8_t)a == a);
52 return (r << GrColor_SHIFT_R) |
53 (g << GrColor_SHIFT_G) |
54 (b << GrColor_SHIFT_B) |
55 (a << GrColor_SHIFT_A);
56 }
57
58 // extract a component (byte) from a GrColor int
59
60 #define GrColorUnpackR(color) (((color) >> GrColor_SHIFT_R) & 0xFF)
61 #define GrColorUnpackG(color) (((color) >> GrColor_SHIFT_G) & 0xFF)
62 #define GrColorUnpackB(color) (((color) >> GrColor_SHIFT_B) & 0xFF)
63 #define GrColorUnpackA(color) (((color) >> GrColor_SHIFT_A) & 0xFF)
64
65 /**
66 * Since premultiplied means that alpha >= color, we construct a color with
67 * each component==255 and alpha == 0 to be "illegal"
68 */
69 #define GrColor_ILLEGAL (~(0xFF << GrColor_SHIFT_A))
70
71 #endif
72
73