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| 1 // Copyright 2015 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "remoting/client/plugin/touch_input_scaler.h" |
| 6 |
| 7 #include "base/logging.h" |
| 8 #include "remoting/proto/event.pb.h" |
| 9 |
| 10 namespace remoting { |
| 11 |
| 12 using protocol::TouchEvent; |
| 13 using protocol::TouchEventPoint; |
| 14 |
| 15 namespace { |
| 16 |
| 17 // |value| is the number to be scaled. |output_max| is the output desktop's max |
| 18 // height or width. |input_max| is the input desktop's max height or width. |
| 19 float Scale(float value, int output_max, int input_max) { |
| 20 DCHECK_GT(output_max, 0); |
| 21 DCHECK_GT(input_max, 0); |
| 22 value *= output_max; |
| 23 value /= input_max; |
| 24 return value; |
| 25 } |
| 26 |
| 27 // Same as Scale() but |value| will be scaled and clamped using |output_max| and |
| 28 // |input_max|. |
| 29 float ScaleAndClamp(float value, int output_max, int input_max) { |
| 30 value = Scale(value, output_max, input_max); |
| 31 return std::max(0.0f, std::min(static_cast<float>(output_max), value)); |
| 32 } |
| 33 |
| 34 } // namespace |
| 35 |
| 36 TouchInputScaler::TouchInputScaler(InputStub* input_stub) |
| 37 : InputFilter(input_stub) {} |
| 38 |
| 39 TouchInputScaler::~TouchInputScaler() {} |
| 40 |
| 41 void TouchInputScaler::InjectTouchEvent(const TouchEvent& event) { |
| 42 if (input_size_.is_empty() || output_size_.is_empty()) |
| 43 return; |
| 44 |
| 45 // We scale based on the maximum input & output coordinates, rather than the |
| 46 // input and output sizes, so that it's possible to reach the edge of the |
| 47 // output when up-scaling. We also take care to round up or down correctly, |
| 48 // which is important when down-scaling. |
| 49 TouchEvent out_event(event); |
| 50 for (int i = 0; i < out_event.touch_points().size(); ++i) { |
| 51 TouchEventPoint* point = out_event.mutable_touch_points(i); |
| 52 if (point->has_x() || point->has_y()) { |
| 53 DCHECK(point->has_x() && point->has_y()); |
| 54 point->set_x( |
| 55 ScaleAndClamp(point->x(), output_size_.width(), input_size_.width())); |
| 56 point->set_y(ScaleAndClamp(point->y(), output_size_.height(), |
| 57 input_size_.height())); |
| 58 } |
| 59 |
| 60 // Also scale the touch size. Without scaling, the size on the host will not |
| 61 // be right. |
| 62 // For example |
| 63 // Suppose: |
| 64 // - No size scaling. |
| 65 // - Client is a HiDPI Chromebook device. |
| 66 // - Host is running on a HiDPI Windows device. |
| 67 // With the configuration above, the client will send the logical touch |
| 68 // size to the host, therefore it will be smaller on the host. |
| 69 // This is because a HiDPI Chromebook device (e.g. Pixel) has 2 by 2 |
| 70 // physical pixel mapped to a logical pixel. |
| 71 // With scaling, the size would be the same. |
| 72 // TODO(rkuroiwa): Also clamp. Note that point->angle() affects the maximum |
| 73 // size (crbug.com/461526). |
| 74 if (point->has_radius_x() || point->has_radius_y()) { |
| 75 DCHECK(point->has_radius_x() && point->has_radius_y()); |
| 76 point->set_radius_x( |
| 77 Scale(point->radius_x(), output_size_.width(), input_size_.width())); |
| 78 point->set_radius_y(Scale(point->radius_y(), output_size_.height(), |
| 79 input_size_.height())); |
| 80 } |
| 81 } |
| 82 |
| 83 InputFilter::InjectTouchEvent(out_event); |
| 84 } |
| 85 |
| 86 } // namespace remoting |
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