1 /*
2  * Copyright 2019 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 #ifndef SkScalingCodec_DEFINED
8 #define SkScalingCodec_DEFINED
9 
10 #include "include/codec/SkCodec.h"
11 
12 // Helper class for an SkCodec that supports arbitrary downscaling.
13 class SkScalingCodec : public SkCodec {
14 protected:
15     SkScalingCodec(SkEncodedInfo&& info, XformFormat srcFormat, std::unique_ptr<SkStream> stream,
16                     SkEncodedOrigin origin = kTopLeft_SkEncodedOrigin)
INHERITED(std::move (info),srcFormat,std::move (stream),origin)17         : INHERITED(std::move(info), srcFormat, std::move(stream), origin) {}
18 
onGetScaledDimensions(float desiredScale)19     SkISize onGetScaledDimensions(float desiredScale) const override {
20         SkISize dim = this->dimensions();
21         // SkCodec treats zero dimensional images as errors, so the minimum size
22         // that we will recommend is 1x1.
23         dim.fWidth = std::max(1, SkScalarRoundToInt(desiredScale * dim.fWidth));
24         dim.fHeight = std::max(1, SkScalarRoundToInt(desiredScale * dim.fHeight));
25         return dim;
26     }
27 
onDimensionsSupported(const SkISize & requested)28     bool onDimensionsSupported(const SkISize& requested) override {
29         SkISize dim = this->dimensions();
30         int w = requested.width();
31         int h = requested.height();
32         return 1 <= w && w <= dim.width() && 1 <= h && h <= dim.height();
33     }
34 
35 private:
36     using INHERITED = SkCodec;
37 };
38 
39 #endif  // SkScalingCodec_DEFINED
40