defer drawing/work until first draw, to make debugging easier and speedup

instantiating the obj just to get its name.



git-svn-id: http://skia.googlecode.com/svn/trunk@3568 2bbb7eff-a529-9590-31e7-b0007b416f81

gm/convexpaths.cpp

@@ -9,13 +9,28 @@
 #include "SkRandom.h"
 #include "SkTArray.h"
 
+class SkOnce : SkNoncopyable {
+public:
+    SkOnce() { fDidOnce = false; }
+    
+    bool needToDo() const { return !fDidOnce; }
+    bool alreadyDone() const { return fDidOnce; }
+    void accomplished() {
+        SkASSERT(!fDidOnce);
+        fDidOnce = true;
+    }
+
+private:
+    bool fDidOnce;
+};
+
 namespace skiagm {
 
 class ConvexPathsGM : public GM {
+    SkOnce fOnce;
 public:
     ConvexPathsGM() {
         this->setBGColor(0xFF000000);
-        this->makePaths();
     }
 
 protected:
@@ -29,6 +44,11 @@ protected:
     }
 
     void makePaths() {
+        if (fOnce.alreadyDone()) {
+            return;
+        }
+        fOnce.accomplished();
+
         // CW
         fPaths.push_back().moveTo(0, 0);
         fPaths.back().quadTo(50 * SK_Scalar1, 100 * SK_Scalar1,
@@ -169,6 +189,7 @@ protected:
     }
 
     virtual void onDraw(SkCanvas* canvas) {
+        this->makePaths();
 
     SkPaint paint;
     paint.setAntiAlias(true);

gm/filltypes.cpp

@@ -14,10 +14,15 @@ class FillTypeGM : public GM {
 public:
 	FillTypeGM() {
         this->setBGColor(0xFFDDDDDD);
+    }
+    
+    void makePath() {
+        if (fPath.isEmpty()) {
             const SkScalar radius = SkIntToScalar(45);
             fPath.addCircle(SkIntToScalar(50), SkIntToScalar(50), radius);
             fPath.addCircle(SkIntToScalar(100), SkIntToScalar(100), radius);
         }
+    }
     
 protected:
     virtual SkString onShortName() {
@@ -57,6 +62,8 @@ protected:
     }
 
     virtual void onDraw(SkCanvas* canvas) {
+        this->makePath();
+
         canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
         
         SkPaint paint;

gm/filltypespersp.cpp

@@ -13,11 +13,15 @@ namespace skiagm {
 class FillTypePerspGM : public GM {
     SkPath fPath;
 public:
-    FillTypePerspGM() {
+    FillTypePerspGM() {}
+    
+    void makePath() {
+        if (fPath.isEmpty()) {
             const SkScalar radius = SkIntToScalar(45);
             fPath.addCircle(SkIntToScalar(50), SkIntToScalar(50), radius);
             fPath.addCircle(SkIntToScalar(100), SkIntToScalar(100), radius);
         }
+    }
     
 protected:
     virtual SkString onShortName() {
@@ -71,6 +75,8 @@ protected:
     }
 
     virtual void onDraw(SkCanvas* canvas) {
+        this->makePath();
+
         // do perspective drawPaint as the background;
         SkPaint bkgnrd;
         SkPoint center = SkPoint::Make(SkIntToScalar(100),