Cary Clark | 5081eed | 2018-01-22 07:55:48 -0500 | [diff] [blame] | 1 | #Topic Automatic_Canvas_Restore |
| 2 | |
| 3 | #Class SkAutoCanvasRestore |
| 4 | |
Cary Clark | 186d08f | 2018-04-03 08:43:27 -0400 | [diff] [blame] | 5 | Stack helper class calls SkCanvas::restoreToCount when SkAutoCanvasRestore |
Cary Clark | 5081eed | 2018-01-22 07:55:48 -0500 | [diff] [blame] | 6 | goes out of scope. Use this to guarantee that the canvas is restored to a known |
| 7 | state. |
| 8 | |
Cary Clark | 682c58d | 2018-05-16 07:07:07 -0400 | [diff] [blame] | 9 | #Subtopic Overview |
| 10 | #Populate |
| 11 | ## |
| 12 | |
Cary Clark | 4855f78 | 2018-02-06 09:41:53 -0500 | [diff] [blame] | 13 | #Subtopic Constructor |
Cary Clark | 08895c4 | 2018-02-01 09:37:32 -0500 | [diff] [blame] | 14 | #Populate |
| 15 | ## |
Cary Clark | 5081eed | 2018-01-22 07:55:48 -0500 | [diff] [blame] | 16 | |
Cary Clark | 4855f78 | 2018-02-06 09:41:53 -0500 | [diff] [blame] | 17 | #Subtopic Member_Function |
Cary Clark | 08895c4 | 2018-02-01 09:37:32 -0500 | [diff] [blame] | 18 | #Populate |
| 19 | ## |
Cary Clark | 5081eed | 2018-01-22 07:55:48 -0500 | [diff] [blame] | 20 | |
| 21 | #Method SkAutoCanvasRestore(SkCanvas* canvas, bool doSave) |
| 22 | |
Cary Clark | ab2621d | 2018-01-30 10:08:57 -0500 | [diff] [blame] | 23 | #Line # preserves Canvas save count ## |
Cary Clark | 5081eed | 2018-01-22 07:55:48 -0500 | [diff] [blame] | 24 | Preserves Canvas save count. Optionally saves Canvas_Clip and Canvas_Matrix. |
| 25 | |
| 26 | #Param canvas Canvas to guard ## |
| 27 | #Param doSave call SkCanvas::save() ## |
| 28 | |
| 29 | #Return utility to restore Canvas state on destructor ## |
| 30 | |
| 31 | #Example |
| 32 | #Height 128 |
| 33 | SkPaint p; |
| 34 | p.setAntiAlias(true); |
| 35 | p.setTextSize(64); |
| 36 | for (SkScalar sx : { -1, 1 } ) { |
| 37 | for (SkScalar sy : { -1, 1 } ) { |
| 38 | SkAutoCanvasRestore autoRestore(canvas, true); |
| 39 | SkMatrix m = SkMatrix::MakeAll(sx, 1, 96, 0, sy, 64, 0, 0, 1); |
| 40 | canvas->concat(m); |
| 41 | canvas->drawString("R", 0, 0, p); |
| 42 | } |
| 43 | } |
| 44 | ## |
| 45 | |
| 46 | #SeeAlso SkCanvas::save SkCanvas::restore |
| 47 | |
| 48 | ## |
| 49 | |
| 50 | #Method ~SkAutoCanvasRestore() |
| 51 | |
Cary Clark | ab2621d | 2018-01-30 10:08:57 -0500 | [diff] [blame] | 52 | #Line # restores Canvas to saved state ## |
Cary Clark | 5081eed | 2018-01-22 07:55:48 -0500 | [diff] [blame] | 53 | Restores Canvas to saved state. Destructor is called when container goes out of |
| 54 | scope. |
| 55 | |
| 56 | #NoExample |
| 57 | ## |
| 58 | |
| 59 | #SeeAlso SkCanvas::save SkCanvas::restore |
| 60 | |
| 61 | ## |
| 62 | |
| 63 | #Method void restore() |
Cary Clark | 78de751 | 2018-02-07 07:27:09 -0500 | [diff] [blame] | 64 | #In Member_Function |
Cary Clark | ab2621d | 2018-01-30 10:08:57 -0500 | [diff] [blame] | 65 | #Line # restores Canvas to saved state ## |
Cary Clark | 5081eed | 2018-01-22 07:55:48 -0500 | [diff] [blame] | 66 | Restores Canvas to saved state immediately. Subsequent calls and |
| 67 | ~SkAutoCanvasRestore have no effect. |
| 68 | |
| 69 | #Example |
| 70 | for (bool callRestore : { false, true } ) { |
| 71 | for (bool saveCanvas : {false, true} ) { |
| 72 | SkAutoCanvasRestore autoRestore(canvas, saveCanvas); |
| 73 | if (!saveCanvas) { |
| 74 | canvas->save(); |
| 75 | } |
| 76 | SkDebugf("saveCanvas: %s before restore: %d\n", |
| 77 | saveCanvas ? "true" : "false", canvas->getSaveCount()); |
| 78 | if (callRestore) autoRestore.restore(); |
| 79 | SkDebugf("saveCanvas: %s after restore: %d\n", |
| 80 | saveCanvas ? "true" : "false", canvas->getSaveCount()); |
| 81 | } |
| 82 | } |
| 83 | SkDebugf("final count: %d\n", canvas->getSaveCount()); |
| 84 | #StdOut |
| 85 | saveCanvas: false before restore: 2 |
| 86 | saveCanvas: false after restore: 2 |
| 87 | saveCanvas: true before restore: 2 |
| 88 | saveCanvas: true after restore: 2 |
| 89 | saveCanvas: false before restore: 2 |
| 90 | saveCanvas: false after restore: 1 |
| 91 | saveCanvas: true before restore: 2 |
| 92 | saveCanvas: true after restore: 1 |
| 93 | final count: 1 |
| 94 | ## |
| 95 | ## |
| 96 | |
| 97 | #SeeAlso SkCanvas::save SkCanvas::restore |
| 98 | |
| 99 | ## |
| 100 | |
| 101 | #Class SkAutoCanvasRestore ## |
| 102 | |
| 103 | #Topic Automatic_Canvas_Restore ## |