mirror of
https://github.com/hajimehoshi/ebiten.git
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65 lines
1.7 KiB
Go
65 lines
1.7 KiB
Go
// Copyright 2018 The Ebiten Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package devicescale
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import (
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"sync"
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)
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type posAndScale struct {
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x, y int
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scale float64
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}
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var (
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m sync.Mutex
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cache []posAndScale
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)
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// GetAt returns the device scale at (x, y), i.e. the number of device-dependent pixels per device-independent pixel.
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// x and y are in device-dependent pixels and must be the top-left coordinate of a monitor, or 0,0 to request a "global scale".
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func GetAt(x, y int) float64 {
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m.Lock()
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defer m.Unlock()
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for _, p := range cache {
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if p.x == x && p.y == y {
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return p.scale
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}
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}
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s := impl(x, y)
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cache = append(cache, posAndScale{
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x: x,
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y: y,
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scale: s,
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})
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return s
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}
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// ClearCache clears the cache.
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// This should be called when monitors are changed by connecting or disconnecting.
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func ClearCache() {
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// TODO: This should be called not only when monitors are changed but also a monitor's scales are changed.
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// The device scale can vary even for the same monitor.
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// The only known case is when the application works on macOS, with OpenGL, with a wider screen mode,
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// and in the fullscreen mode (#1573).
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m.Lock()
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defer m.Unlock()
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cache = cache[:0]
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}
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