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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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