Suggested version with 'undo'.

BUG=skia:

Review URL: https://codereview.chromium.org/931483002

3 files changed, 73 insertions, 11 deletions

diff --git a/dm/DM.cpp b/dm/DM.cpp
index 5745113096..b41a77f8ad 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -21,8 +21,9 @@ DEFINE_bool(nameByHash, false,
             "If true, write to FLAGS_writePath[0]/<hash>.png instead of "
             "to FLAGS_writePath[0]/<config>/<sourceType>/<name>.png");
 DEFINE_bool2(pathOpsExtended, x, false, "Run extended pathOps tests.");
-DEFINE_string(matrix, "1 0 0 0 1 0 0 0 1",
-              "Matrix to apply when using 'matrix' in config.");
+DEFINE_string(matrix, "1 0 0 1",
+              "2x2 scale+skew matrix to apply or upright when using "
+              "'matrix' or 'upright' in config.");
 DEFINE_bool(gpu_threading, false, "Allow GPU work to run on multiple threads?");
 
 DEFINE_string(blacklist, "",
@@ -242,12 +243,15 @@ static Sink* create_via(const char* tag, Sink* wrapped) {
     VIA("tiles",     ViaTiles, 256, 256,               NULL, wrapped);
     VIA("tiles_rt",  ViaTiles, 256, 256, new SkRTreeFactory, wrapped);
 
-    if (FLAGS_matrix.count() == 9) {
+    if (FLAGS_matrix.count() == 4) {
         SkMatrix m;
-        for (int i = 0; i < 9; i++) {
-            m[i] = (SkScalar)atof(FLAGS_matrix[i]);
-        }
-        VIA("matrix", ViaMatrix, m, wrapped);
+        m.reset();
+        m.setScaleX((SkScalar)atof(FLAGS_matrix[0]));
+        m.setSkewX ((SkScalar)atof(FLAGS_matrix[1]));
+        m.setSkewY ((SkScalar)atof(FLAGS_matrix[2]));
+        m.setScaleY((SkScalar)atof(FLAGS_matrix[3]));
+        VIA("matrix",  ViaMatrix,  m, wrapped);
+        VIA("upright", ViaUpright, m, wrapped);
     }
 #undef VIA
     return NULL;
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index 4e3668f15e..b44f1d7818 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -271,25 +271,71 @@ Error RasterSink::draw(const Src& src, SkBitmap* dst, SkWStream*, SkString*) con
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
+static SkISize auto_compute_translate(SkMatrix* matrix, int srcW, int srcH) {
+    SkRect bounds = SkRect::MakeIWH(srcW, srcH);
+    matrix->mapRect(&bounds);
+    matrix->postTranslate(-bounds.x(), -bounds.y());
+    return SkISize::Make(SkScalarRoundToInt(bounds.width()), SkScalarRoundToInt(bounds.height()));
+}
+
 ViaMatrix::ViaMatrix(SkMatrix matrix, Sink* sink) : fMatrix(matrix), fSink(sink) {}
 
 Error ViaMatrix::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
     // We turn our arguments into a Src, then draw that Src into our Sink to fill bitmap or stream.
     struct ProxySrc : public Src {
-        const Src& fSrc;
-        SkMatrix fMatrix;
-        ProxySrc(const Src& src, SkMatrix matrix) : fSrc(src), fMatrix(matrix) {}
+        const Src&  fSrc;
+        SkMatrix    fMatrix;
+        SkISize     fSize;
+
+        ProxySrc(const Src& src, SkMatrix matrix) : fSrc(src), fMatrix(matrix) {
+            fSize = auto_compute_translate(&fMatrix, src.size().width(), src.size().height());
+        }
 
         Error draw(SkCanvas* canvas) const SK_OVERRIDE {
             canvas->concat(fMatrix);
             return fSrc.draw(canvas);
         }
-        SkISize size() const SK_OVERRIDE { return fSrc.size(); }
+        SkISize size() const SK_OVERRIDE { return fSize; }
         Name name() const SK_OVERRIDE { sk_throw(); return ""; }  // No one should be calling this.
     } proxy(src, fMatrix);
     return fSink->draw(proxy, bitmap, stream, log);
 }
 
+// Undoes any flip or 90 degree rotate without changing the scale of the bitmap.
+// This should be pixel-preserving.
+ViaUpright::ViaUpright(SkMatrix matrix, Sink* sink) : fMatrix(matrix), fSink(sink) {}
+
+Error ViaUpright::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
+    Error err = fSink->draw(src, bitmap, stream, log);
+    if (!err.isEmpty()) {
+        return err;
+    }
+
+    SkMatrix inverse;
+    if (!fMatrix.rectStaysRect() || !fMatrix.invert(&inverse)) {
+        return "Cannot upright --matrix.";
+    }
+    SkMatrix upright = SkMatrix::I();
+    upright.setScaleX(SkScalarSignAsScalar(inverse.getScaleX()));
+    upright.setScaleY(SkScalarSignAsScalar(inverse.getScaleY()));
+    upright.setSkewX(SkScalarSignAsScalar(inverse.getSkewX()));
+    upright.setSkewY(SkScalarSignAsScalar(inverse.getSkewY()));
+
+    SkBitmap uprighted;
+    SkISize size = auto_compute_translate(&upright, bitmap->width(), bitmap->height());
+    uprighted.allocPixels(bitmap->info().makeWH(size.width(), size.height()));
+
+    SkCanvas canvas(uprighted);
+    canvas.concat(upright);
+    SkPaint paint;
+    paint.setXfermodeMode(SkXfermode::kSrc_Mode);
+    canvas.drawBitmap(*bitmap, 0, 0, &paint);
+
+    *bitmap = uprighted;
+    bitmap->lockPixels();
+    return "";
+}
+
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
 ViaPipe::ViaPipe(Sink* sink) : fSink(sink) {}
diff --git a/dm/DMSrcSink.h b/dm/DMSrcSink.h
index 4c15c92cb6..abf3ef8a2f 100644
--- a/dm/DMSrcSink.h
+++ b/dm/DMSrcSink.h
@@ -163,6 +163,18 @@ private:
     SkAutoTDelete<Sink> fSink;
 };
 
+class ViaUpright : public Sink {
+public:
+    ViaUpright(SkMatrix, Sink*);
+
+    Error draw(const Src&, SkBitmap*, SkWStream*, SkString*) const SK_OVERRIDE;
+    int enclave() const SK_OVERRIDE { return fSink->enclave(); }
+    const char* fileExtension() const SK_OVERRIDE { return fSink->fileExtension(); }
+private:
+    SkMatrix            fMatrix;
+    SkAutoTDelete<Sink> fSink;
+};
+
 class ViaPipe : public Sink {
 public:
     explicit ViaPipe(Sink*);