docs/SkAutoCanvasRestore_Reference.bmh

#Topic Automatic_Canvas_Restore

#Class SkAutoCanvasRestore

Stack helper class calls SkCanvas::restoreToCount() when SkAutoCanvasRestore
goes out of scope. Use this to guarantee that the canvas is restored to a known
state.

#Topic Overview

#Subtopic Subtopics
#ToDo manually add subtopics ##
#Table
#Legend
# name             # description                                   ##
#Legend ##
# Constructors     # functions that construct SkAutoCanvasRestore  ##
# Member_Functions # static functions and member methods           ##
#Table ##
#Subtopic ##

#Subtopic Constructors
#Table
#Legend
# name                                               # description                     ##
#Legend ##
# SkAutoCanvasRestore(SkCanvas* canvas, bool doSave) # Preserves Canvas save count.    ##
# ~SkAutoCanvasRestore()                             # Restores Canvas to saved state. ##
#Table ##
#Subtopic ##

#Subtopic Member_Functions
#Table
#Legend
# name                             # description                     ##
#Legend ##
# restore()                        # Restores Canvas to saved state. ##
#Table ##
#Subtopic ##

#Topic Overview ##

#Method SkAutoCanvasRestore(SkCanvas* canvas, bool doSave)

Preserves Canvas save count. Optionally saves Canvas_Clip and Canvas_Matrix.

#Param canvas  Canvas to guard ##
#Param doSave  call SkCanvas::save() ##

#Return utility to restore Canvas state on destructor ##

#Example
#Height 128
    SkPaint p;
    p.setAntiAlias(true);
    p.setTextSize(64);
    for (SkScalar sx : { -1, 1 } ) {
        for (SkScalar sy : { -1, 1 } ) {
            SkAutoCanvasRestore autoRestore(canvas, true);
            SkMatrix m = SkMatrix::MakeAll(sx, 1, 96,    0, sy, 64,   0, 0, 1);
            canvas->concat(m);
            canvas->drawString("R", 0, 0, p);
        }
    }
##

#SeeAlso SkCanvas::save SkCanvas::restore

##

#Method ~SkAutoCanvasRestore()

Restores Canvas to saved state. Destructor is called when container goes out of
scope.

#NoExample
##

#SeeAlso SkCanvas::save SkCanvas::restore

##

#Method void restore()

Restores Canvas to saved state immediately. Subsequent calls and
~SkAutoCanvasRestore have no effect.

#Example
for (bool callRestore : { false, true } ) {
    for (bool saveCanvas : {false, true} ) {
        SkAutoCanvasRestore autoRestore(canvas, saveCanvas);
        if (!saveCanvas) {
            canvas->save();
        }
        SkDebugf("saveCanvas: %s  before restore: %d\n",
               saveCanvas ? "true" : "false", canvas->getSaveCount());
        if (callRestore) autoRestore.restore();
        SkDebugf("saveCanvas: %s  after restore: %d\n",
               saveCanvas ? "true" : "false", canvas->getSaveCount());
    }
}
SkDebugf("final count: %d\n", canvas->getSaveCount());
#StdOut
saveCanvas: false  before restore: 2
saveCanvas: false  after restore: 2
saveCanvas: true  before restore: 2
saveCanvas: true  after restore: 2
saveCanvas: false  before restore: 2
saveCanvas: false  after restore: 1
saveCanvas: true  before restore: 2
saveCanvas: true  after restore: 1
final count: 1
##
##

#SeeAlso SkCanvas::save SkCanvas::restore

##

#Class SkAutoCanvasRestore ##

#Topic Automatic_Canvas_Restore ##