add unittest for SkTreatAsSprite
Review URL: https://codereview.appspot.com/7042044
git-svn-id: http://skia.googlecode.com/svn/trunk@6974 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkMatrix.cpp b/src/core/SkMatrix.cpp
index 8dee0cb..4845f59 100644
--- a/src/core/SkMatrix.cpp
+++ b/src/core/SkMatrix.cpp
@@ -1802,3 +1802,52 @@
SkFractToFloat(fMat[6]), SkFractToFloat(fMat[7]), SkFractToFloat(fMat[8]));
#endif
}
+
+///////////////////////////////////////////////////////////////////////////////
+
+#include "SkMatrixUtils.h"
+
+bool SkTreatAsSprite(const SkMatrix& mat, const SkRect& src,
+ unsigned subpixelBits) {
+ if (mat.getType() & ~(SkMatrix::kScale_Mask | SkMatrix::kTranslate_Mask)) {
+ return false;
+ }
+
+ // quick success check
+ if (!subpixelBits && !(mat.getType() & ~SkMatrix::kTranslate_Mask)) {
+ return true;
+ }
+
+ // mapRect supports negative scales, so we eliminate those first
+ if (mat.getScaleX() < 0 || mat.getScaleY() < 0) {
+ return false;
+ }
+
+ SkRect dst;
+ SkIRect isrc, idst;
+
+ mat.mapRect(&dst, src);
+
+ {
+ SkRect tmp = src;
+ tmp.offset(mat.getTranslateX(), mat.getTranslateY());
+ tmp.round(&isrc);
+ }
+
+ if (subpixelBits) {
+ isrc.fLeft <<= subpixelBits;
+ isrc.fTop <<= subpixelBits;
+ isrc.fRight <<= subpixelBits;
+ isrc.fBottom <<= subpixelBits;
+
+ const float scale = 1 << subpixelBits;
+ dst.fLeft *= scale;
+ dst.fTop *= scale;
+ dst.fRight *= scale;
+ dst.fBottom *= scale;
+ }
+
+ dst.round(&idst);
+ return isrc == idst;
+}
+
diff --git a/src/core/SkMatrixUtils.h b/src/core/SkMatrixUtils.h
new file mode 100644
index 0000000..db7370c
--- /dev/null
+++ b/src/core/SkMatrixUtils.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkMatrixUtils_DEFINED
+#define SkMatrixUtils_DEFINED
+
+#include "SkMatrix.h"
+
+/**
+ * Number of subpixel bits used in skia's bilerp.
+ * See SkBitmapProcState_procs.h and SkBitmapProcState_filter.h
+ */
+#define kSkSubPixelBitsForBilerp 4
+
+/**
+ * Given a matrix and a src-rect, return true if the computed dst-rect would
+ * align such that there is a 1-to-1 coorspondence between src and dst pixels.
+ * This can be called by drawing code to see if drawBitmap can be turned into
+ * drawSprite (which is faster).
+ *
+ * The "closeness" test is based on the subpixelBits parameter. Pass 0 for
+ * round-to-nearest behavior (e.g. nearest neighbor sampling). Pass the number
+ * of subpixel-bits to simulate filtering.
+ */
+bool SkTreatAsSprite(const SkMatrix&, const SkRect& src, unsigned subpixelBits);
+
+
+#endif
diff --git a/tests/DrawBitmapRectTest.cpp b/tests/DrawBitmapRectTest.cpp
index 7dc51c0..0a8d730 100644
--- a/tests/DrawBitmapRectTest.cpp
+++ b/tests/DrawBitmapRectTest.cpp
@@ -9,6 +9,90 @@
#include "SkBitmap.h"
#include "SkCanvas.h"
#include "SkShader.h"
+#include "SkRandom.h"
+#include "SkMatrixUtils.h"
+
+static void rand_matrix(SkMatrix* mat, SkRandom& rand, unsigned mask) {
+ mat->setIdentity();
+ if (mask & SkMatrix::kTranslate_Mask) {
+ mat->postTranslate(rand.nextSScalar1(), rand.nextSScalar1());
+ }
+ if (mask & SkMatrix::kScale_Mask) {
+ mat->postScale(rand.nextSScalar1(), rand.nextSScalar1());
+ }
+ if (mask & SkMatrix::kAffine_Mask) {
+ mat->postRotate(rand.nextSScalar1() * 360);
+ }
+ if (mask & SkMatrix::kPerspective_Mask) {
+ mat->setPerspX(rand.nextSScalar1());
+ mat->setPerspY(rand.nextSScalar1());
+ }
+}
+
+static void rand_rect(SkRect* r, SkRandom& rand) {
+ r->set(rand.nextSScalar1() * 1000, rand.nextSScalar1() * 1000,
+ rand.nextSScalar1() * 1000, rand.nextSScalar1() * 1000);
+ r->sort();
+}
+
+static void test_treatAsSprite(skiatest::Reporter* reporter) {
+ const unsigned bilerBits = kSkSubPixelBitsForBilerp;
+
+ SkMatrix mat;
+ SkRect r;
+ SkRandom rand;
+
+ // assert: translate-only no-filter can always be treated as sprite
+ for (int i = 0; i < 1000; ++i) {
+ rand_matrix(&mat, rand, SkMatrix::kTranslate_Mask);
+ for (int j = 0; j < 1000; ++j) {
+ rand_rect(&r, rand);
+ REPORTER_ASSERT(reporter, SkTreatAsSprite(mat, r, 0));
+ }
+ }
+
+ // assert: rotate/perspect is never treated as sprite
+ for (int i = 0; i < 1000; ++i) {
+ rand_matrix(&mat, rand, SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask);
+ for (int j = 0; j < 1000; ++j) {
+ rand_rect(&r, rand);
+ REPORTER_ASSERT(reporter, !SkTreatAsSprite(mat, r, 0));
+ REPORTER_ASSERT(reporter, !SkTreatAsSprite(mat, r, bilerBits));
+ }
+ }
+
+ r.set(10, 10, 500, 600);
+
+ const SkScalar tooMuchSubpixel = SkFloatToScalar(100.1f);
+ mat.setTranslate(tooMuchSubpixel, 0);
+ REPORTER_ASSERT(reporter, !SkTreatAsSprite(mat, r, bilerBits));
+ mat.setTranslate(0, tooMuchSubpixel);
+ REPORTER_ASSERT(reporter, !SkTreatAsSprite(mat, r, bilerBits));
+
+ const SkScalar tinySubPixel = SkFloatToScalar(100.02f);
+ mat.setTranslate(tinySubPixel, 0);
+ REPORTER_ASSERT(reporter, SkTreatAsSprite(mat, r, bilerBits));
+ mat.setTranslate(0, tinySubPixel);
+ REPORTER_ASSERT(reporter, SkTreatAsSprite(mat, r, bilerBits));
+
+ const SkScalar twoThirds = SK_Scalar1 * 2 / 3;
+ const SkScalar bigScale = SkScalarDiv(r.width() + twoThirds, r.width());
+ mat.setScale(bigScale, bigScale);
+ REPORTER_ASSERT(reporter, !SkTreatAsSprite(mat, r, false));
+ REPORTER_ASSERT(reporter, !SkTreatAsSprite(mat, r, bilerBits));
+
+ const SkScalar oneThird = SK_Scalar1 / 3;
+ const SkScalar smallScale = SkScalarDiv(r.width() + oneThird, r.width());
+ mat.setScale(smallScale, smallScale);
+ REPORTER_ASSERT(reporter, SkTreatAsSprite(mat, r, false));
+ REPORTER_ASSERT(reporter, !SkTreatAsSprite(mat, r, bilerBits));
+
+ const SkScalar oneFortyth = SK_Scalar1 / 40;
+ const SkScalar tinyScale = SkScalarDiv(r.width() + oneFortyth, r.width());
+ mat.setScale(tinyScale, tinyScale);
+ REPORTER_ASSERT(reporter, SkTreatAsSprite(mat, r, false));
+ REPORTER_ASSERT(reporter, SkTreatAsSprite(mat, r, bilerBits));
+}
static void assert_ifDrawnTo(skiatest::Reporter* reporter,
const SkBitmap& bm, bool shouldBeDrawn) {
@@ -179,6 +263,8 @@
test_nan_antihair(reporter);
test_giantrepeat_crbug118018(reporter);
+
+ test_treatAsSprite(reporter);
}
#include "TestClassDef.h"