1 /* libs/graphics/sgl/SkBlitter_A1.cpp
2 **
3 ** Copyright 2006, The Android Open Source Project
4 **
5 ** Licensed under the Apache License, Version 2.0 (the "License");
6 ** you may not use this file except in compliance with the License.
7 ** You may obtain a copy of the License at
8 **
9 ** http://www.apache.org/licenses/LICENSE-2.0
10 **
11 ** Unless required by applicable law or agreed to in writing, software
12 ** distributed under the License is distributed on an "AS IS" BASIS,
13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 ** See the License for the specific language governing permissions and
15 ** limitations under the License.
16 */
17
18 #include "SkCoreBlitters.h"
19
SkA1_Blitter(const SkBitmap & device,const SkPaint & paint)20 SkA1_Blitter::SkA1_Blitter(const SkBitmap& device, const SkPaint& paint)
21 : INHERITED(device) {
22 fSrcA = paint.getAlpha();
23 }
24
blitH(int x,int y,int width)25 void SkA1_Blitter::blitH(int x, int y, int width) {
26 SkASSERT(x >= 0 && y >= 0 &&
27 (unsigned)(x + width) <= (unsigned)fDevice.width());
28
29 if (fSrcA <= 0x7F) {
30 return;
31 }
32 uint8_t* dst = fDevice.getAddr1(x, y);
33 int right = x + width;
34
35 int left_mask = 0xFF >> (x & 7);
36 int rite_mask = 0xFF << (8 - (right & 7));
37 int full_runs = (right >> 3) - ((x + 7) >> 3);
38
39 // check for empty right mask, so we don't read off the end
40 // (or go slower than we need to)
41 if (rite_mask == 0) {
42 SkASSERT(full_runs >= 0);
43 full_runs -= 1;
44 rite_mask = 0xFF;
45 }
46 if (left_mask == 0xFF) {
47 full_runs -= 1;
48 }
49 if (full_runs < 0) {
50 SkASSERT((left_mask & rite_mask) != 0);
51 *dst |= (left_mask & rite_mask);
52 } else {
53 *dst++ |= left_mask;
54 memset(dst, 0xFF, full_runs);
55 dst += full_runs;
56 *dst |= rite_mask;
57 }
58 }
59
60