Alternate version of SkLocalMatrixImageFilter using an input.

src/core/SkLocalMatrixImageFilter.cpp

Index: src/core/SkLocalMatrixImageFilter.cpp
diff --git a/src/core/SkLocalMatrixImageFilter.cpp b/src/core/SkLocalMatrixImageFilter.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..eb2f84c89fbbd71687668d6b45ef12de885070a6
--- /dev/null
+++ b/src/core/SkLocalMatrixImageFilter.cpp
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkImageFilter.h"
+#include "SkReadBuffer.h"
+#include "SkString.h"
+
+/**
+ *  Wraps another imagefilter + matrix, such that using this filter will give the same result
+ *  as using the wrapped filter with the matrix applied to its context.
+ */
+class SkLocalMatrixImageFilter : public SkImageFilter {
+public:
+    static SkImageFilter* Create(SkImageFilter* base, const SkMatrix& localM) {
+        if (localM.getType() & (SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask)) {
+            return nullptr;
+        }
+        if (localM.isIdentity()) {

[robertphillips, 2015/10/13 19:42:39]

readd this ?

[Stephen White, 2015/10/13 20:12:40]

Done.

+       //     return SkRef(base);
+        }
+        return new SkLocalMatrixImageFilter(base, localM);
+    }
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLocalMatrixImageFilter)
+
+protected:
+    void flatten(SkWriteBuffer&) const override;
+    bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
+                       SkBitmap* result, SkIPoint* offset) const override;
+    bool onFilterBounds(const SkIRect& src, const SkMatrix&, SkIRect* dst) const override;
+
+private:
+    SkLocalMatrixImageFilter(SkImageFilter* base, const SkMatrix& localM)
+        : INHERITED(1, &base), fLocalM(localM)
+    {}
+
+    SkMatrix                    fLocalM;
+
+    typedef SkImageFilter INHERITED;
+};
+

[robertphillips, 2015/10/13 19:42:39]

use SkMatrix::Concat ?

[Stephen White, 2015/10/13 20:12:40]

Done.

+static SkMatrix concat(const SkMatrix& a, const SkMatrix& b) {
+    SkMatrix c;
+    c.setConcat(a, b);
+    return c;
+}
+
+SkFlattenable* SkLocalMatrixImageFilter::CreateProc(SkReadBuffer& buffer) {
+    SK_IMAGEFILTER_UNFLATTEN_COMMON(common, 1);
+    SkMatrix lm;
+    buffer.readMatrix(&lm);
+    return SkLocalMatrixImageFilter::Create(common.getInput(0), lm);
+}
+
+void SkLocalMatrixImageFilter::flatten(SkWriteBuffer& buffer) const {
+    this->INHERITED::flatten(buffer);
+    buffer.writeMatrix(fLocalM);
+}
+
+bool SkLocalMatrixImageFilter::onFilterImage(Proxy* proxy, const SkBitmap& src, const Context& ctx,
+                                             SkBitmap* result, SkIPoint* offset) const {
+    Context localCtx(concat(ctx.ctm(), fLocalM), ctx.clipBounds(), ctx.cache());

[robertphillips, 2015/10/13 19:42:39]

this-> on the getInputs ?

[Stephen White, 2015/10/13 20:12:40]

Done.

+    return getInput(0) && getInput(0)->filterImage(proxy, src, localCtx, result, offset);
+}
+
+bool SkLocalMatrixImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& matrix,
+                                              SkIRect* dst) const {

[robertphillips, 2015/10/13 19:42:39]

this-> here too ?

[Stephen White, 2015/10/13 20:12:40]

Done.

+    return getInput(0) && getInput(0)->onFilterBounds(src, concat(matrix, fLocalM), dst);
+}
+
+#ifndef SK_IGNORE_TO_STRING
+void SkLocalMatrixImageFilter::toString(SkString* str) const {
+    str->append("SkLocalMatrixImageFilter: (");
+    str->append(")");
+}
+#endif
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+SkImageFilter* SkImageFilter::newWithLocalMatrix(const SkMatrix& localMatrix) const {
+    return SkLocalMatrixImageFilter::Create(const_cast<SkImageFilter*>(this), localMatrix);
+}