add tests for extractAlpha
git-svn-id: http://skia.googlecode.com/svn/trunk@346 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleExtractAlpha.cpp b/samplecode/SampleExtractAlpha.cpp
new file mode 100644
index 0000000..37c49a0
--- /dev/null
+++ b/samplecode/SampleExtractAlpha.cpp
@@ -0,0 +1,93 @@
+#include "SampleCode.h"
+#include "SkColorPriv.h"
+#include "SkGradientShader.h"
+#include "SkView.h"
+#include "SkCanvas.h"
+#include "SkUtils.h"
+
+static SkBitmap make_bitmap() {
+ SkBitmap bm;
+ SkColorTable* ctable = new SkColorTable(256);
+
+ SkPMColor* c = ctable->lockColors();
+ for (int i = 0; i < 256; i++) {
+ c[i] = SkPackARGB32(255 - i, 0, 0, 0);
+ }
+ ctable->unlockColors(true);
+ bm.setConfig(SkBitmap::kIndex8_Config, 256, 256);
+ bm.allocPixels(ctable);
+ ctable->unref();
+
+ bm.lockPixels();
+ const float cx = bm.width() * 0.5f;
+ const float cy = bm.height() * 0.5f;
+ for (int y = 0; y < bm.height(); y++) {
+ float dy = y - cy;
+ dy *= dy;
+ uint8_t* p = bm.getAddr8(0, y);
+ for (int x = 0; x < 256; x++) {
+ float dx = x - cx;
+ dx *= dx;
+ float d = (dx + dy) / (cx/2);
+ int id = (int)d;
+ if (id > 255) {
+ id = 255;
+ }
+ p[x] = id;
+ }
+ }
+ bm.unlockPixels();
+ return bm;
+}
+
+class ExtractAlphaView : public SkView {
+ SkBitmap fBM8;
+ SkBitmap fBM32;
+ SkBitmap fBM4;
+public:
+ ExtractAlphaView() {
+ fBM8 = make_bitmap();
+ fBM8.copyTo(&fBM32, SkBitmap::kARGB_8888_Config);
+ fBM8.copyTo(&fBM4, SkBitmap::kARGB_4444_Config);
+ }
+
+protected:
+ // overrides from SkEventSink
+ virtual bool onQuery(SkEvent* evt) {
+ if (SampleCode::TitleQ(*evt)) {
+ SampleCode::TitleR(evt, "DitherBitmap");
+ return true;
+ }
+ return this->INHERITED::onQuery(evt);
+ }
+
+ void drawBG(SkCanvas* canvas) {
+ canvas->drawColor(0xFFDDDDDD);
+ }
+
+ virtual void onDraw(SkCanvas* canvas) {
+ drawBG(canvas);
+
+ const SkBitmap* srcBM[] = { &fBM8, &fBM32, &fBM4 };
+
+ SkPaint paint;
+ paint.setColor(SK_ColorRED);
+ for (int i = 0; i < 3; i++) {
+ canvas->drawBitmap(*srcBM[i], 0, 0, &paint);
+ SkBitmap tmp;
+ srcBM[i]->extractAlpha(&tmp);
+ canvas->drawBitmap(tmp, 0, SkIntToScalar(tmp.height() + 10), &paint);
+
+ canvas->translate(SkIntToScalar(tmp.width() + 10), 0);
+ }
+ }
+
+private:
+ typedef SkView INHERITED;
+};
+
+//////////////////////////////////////////////////////////////////////////////
+
+static SkView* MyFactory() { return new ExtractAlphaView; }
+static SkViewRegister reg(MyFactory);
+