Implement a generic matrix transform image filter.

include/effects/SkTransformImageFilter.h

+/*
+ * Copyright 2014 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkTransformImageFilter_DEFINED
+#define SkTransformImageFilter_DEFINED
+
+#include "SkImageFilter.h"
+#include "SkScalar.h"
+#include "SkSize.h"
+#include "SkPoint.h"
+#include "SkPaint.h"
+
+/*! \class SkTransformImageFilter
+    Matrix transformation image filter.  This filter draws its source
+    input transformed by the given matrix.
+ */
+
+class SK_API SkTransformImageFilter : public SkImageFilter {

[reed1, 2014/03/25 16:04:04]

bikeshed: SkMatrixImageFilter -- since it takes a matrix and skia talks in terms
of matrices, not transforms.

+public:
+    /** Construct a 2D transformation image filter.
+     *  @param transform    The matrix to apply when drawing the src bitmap
+     *  @param filterLevel  The quality of filtering to apply when scaling.
+     *  @param input        The input image filter.  If NULL, the src bitmap
+     *                      passed to filterImage() is used instead.
+     */
+
+    static SkTransformImageFilter* Create(const SkMatrix& transform,
+                                          SkPaint::FilterLevel,
+                                          SkImageFilter* input = NULL);
+    virtual ~SkTransformImageFilter();
+
+    virtual void computeFastBounds(const SkRect&, SkRect*) const SK_OVERRIDE;
+
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkTransformImageFilter)
+
+protected:
+    SkTransformImageFilter(const SkMatrix& transform,
+                           SkPaint::FilterLevel,
+                           SkImageFilter* input = NULL);
+    SkTransformImageFilter(SkReadBuffer& buffer);
+    virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
+
+    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
+                               SkBitmap* result, SkIPoint* loc) const SK_OVERRIDE;
+    virtual bool onFilterBounds(const SkIRect& src, const SkMatrix&,
+                                SkIRect* dst) const SK_OVERRIDE;
+
+private:
+    SkMatrix              fTransform;
+    SkPaint::FilterLevel  fFilterLevel;
+    typedef SkImageFilter INHERITED;
+};
+
+#endif