Exit SkBitmap::scrollRect() early if width <= 0
As suggested in email from saintlou@google.com
Review URL: http://codereview.appspot.com/4806047
git-svn-id: http://skia.googlecode.com/svn/trunk@1948 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/bitmapscroll.cpp b/gm/bitmapscroll.cpp
new file mode 100644
index 0000000..de7130d
--- /dev/null
+++ b/gm/bitmapscroll.cpp
@@ -0,0 +1,136 @@
+#include "gm.h"
+
+namespace skiagm {
+
+/** Create a bitmap image suitable for testing SkBitmap::scrollRect().
+ *
+ * @param quarterWidth bitmap will be 4x this many pixels wide
+ * @param quarterHeight bitmap will be 4x this many pixels tall
+ * @param bitmap the bitmap data is written into this object
+ */
+static void make_bitmap(int quarterWidth, int quarterHeight, SkBitmap *bitmap) {
+ SkPaint pRed, pWhite, pGreen, pBlue, pLine;
+ pRed.setColor(0xFFFF9999);
+ pWhite.setColor(0xFFFFFFFF);
+ pGreen.setColor(0xFF99FF99);
+ pBlue.setColor(0xFF9999FF);
+ pLine.setColor(0xFF000000);
+ pLine.setStyle(SkPaint::kStroke_Style);
+
+ // Prepare bitmap, and a canvas that draws into it.
+ bitmap->reset();
+ bitmap->setConfig(SkBitmap::kARGB_8888_Config,
+ quarterWidth*4, quarterHeight*4);
+ bitmap->allocPixels();
+ SkCanvas canvas(*bitmap);
+
+ SkScalar w = SkIntToScalar(quarterWidth);
+ SkScalar h = SkIntToScalar(quarterHeight);
+ canvas.drawRectCoords( 0, 0, w*2, h*2, pRed);
+ canvas.drawRectCoords(w*2, 0, w*4, h*2, pGreen);
+ canvas.drawRectCoords( 0, h*2, w*2, h*4, pBlue);
+ canvas.drawRectCoords(w*2, h*2, w*4, h*4, pWhite);
+ canvas.drawLine(w*2, 0, w*2, h*4, pLine);
+ canvas.drawLine( 0, h*2, w*4, h*2, pLine);
+ canvas.drawRectCoords(w, h, w*3, h*3, pLine);
+}
+
+class BitmapScrollGM : public GM {
+public:
+ BitmapScrollGM() {
+ // Create the original bitmap.
+ make_bitmap(quarterWidth, quarterHeight, &origBitmap);
+ }
+
+protected:
+ virtual SkString onShortName() {
+ return SkString("bitmapscroll");
+ }
+
+ virtual SkISize onISize() {
+ return make_isize(800, 600);
+ }
+
+ virtual void onDraw(SkCanvas* canvas) {
+ SkIRect scrollCenterRegion = SkIRect::MakeXYWH(
+ quarterWidth, quarterHeight, quarterWidth*2, quarterHeight*2);
+ int x = quarterWidth;
+ int y = quarterHeight;
+ int xSpacing = quarterWidth * 20;
+ int ySpacing = quarterHeight * 16;
+
+ // Draw background and left-hand text labels.
+ canvas->drawColor(0xFFDDDDDD);
+ drawLabel(canvas, "scroll entire bitmap",
+ x, y, x, y + ySpacing);
+ drawLabel(canvas, "scroll part of bitmap",
+ x, y + ySpacing, x, y + ySpacing*2);
+ x += 30;
+
+ // Draw various permutations of scrolled bitmaps, scrolling a bit
+ // further each time.
+ draw9(canvas, x, y, NULL, quarterWidth*1/2, quarterHeight*1/2);
+ draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
+ quarterWidth*1/2, quarterHeight*1/2);
+ x += xSpacing;
+ draw9(canvas, x, y, NULL, quarterWidth*3/2, quarterHeight*3/2);
+ draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
+ quarterWidth*3/2, quarterHeight*3/2);
+ x += xSpacing;
+ draw9(canvas, x, y, NULL, quarterWidth*5/2, quarterHeight*5/2);
+ draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
+ quarterWidth*5/2, quarterHeight*5/2);
+ x += xSpacing;
+ draw9(canvas, x, y, NULL, quarterWidth*9/2, quarterHeight*9/2);
+ draw9(canvas, x, y+ySpacing, &scrollCenterRegion,
+ quarterWidth*9/2, quarterHeight*9/2);
+ }
+
+ void drawLabel(SkCanvas* canvas, const char *text, int startX, int startY,
+ int endX, int endY) {
+ SkPaint paint;
+ paint.setColor(0xFF000000);
+ SkPath path;
+ path.moveTo(SkIntToScalar(startX), SkIntToScalar(startY));
+ path.lineTo(SkIntToScalar(endX), SkIntToScalar(endY));
+ canvas->drawTextOnPath(text, strlen(text), path, NULL, paint);
+ }
+
+ /** Stamp out 9 copies of origBitmap, scrolled in each direction (and
+ * not scrolled at all).
+ */
+ void draw9(SkCanvas* canvas, int x, int y, SkIRect* subset,
+ int scrollX, int scrollY) {
+ for (int yMult=-1; yMult<=1; yMult++) {
+ for (int xMult=-1; xMult<=1; xMult++) {
+ // Figure out the (x,y) to draw this copy at
+ SkScalar bitmapX = SkIntToScalar(
+ x + quarterWidth * 5 * (xMult+1));
+ SkScalar bitmapY = SkIntToScalar(
+ y + quarterHeight * 5 * (yMult+1));
+
+ // Scroll a new copy of the bitmap, and then draw it.
+ // scrollRect() should always return true, even if it's a no-op
+ SkBitmap scrolledBitmap;
+ SkASSERT(origBitmap.copyTo(
+ &scrolledBitmap, origBitmap.config()));
+ SkASSERT(scrolledBitmap.scrollRect(
+ subset, scrollX * xMult, scrollY * yMult));
+ canvas->drawBitmap(scrolledBitmap, bitmapX, bitmapY);
+ }
+ }
+ }
+
+private:
+ typedef GM INHERITED;
+ static const int quarterWidth = 10;
+ static const int quarterHeight = 14;
+ SkBitmap origBitmap;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static GM* MyFactory(void*) { return new BitmapScrollGM; }
+static GMRegistry reg(MyFactory);
+
+}
diff --git a/gm/gm.h b/gm/gm.h
index ab92ff6..ce10ec7 100644
--- a/gm/gm.h
+++ b/gm/gm.h
@@ -1,7 +1,9 @@
#ifndef skiagm_DEFINED
#define skiagm_DEFINED
+#include "SkBitmap.h"
#include "SkCanvas.h"
+#include "SkDevice.h"
#include "SkPaint.h"
#include "SkRefCnt.h"
#include "SkSize.h"