48 lines
1.2 KiB
Go
48 lines
1.2 KiB
Go
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// 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 pos struct {
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x, y int
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}
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var (
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m sync.Mutex
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cache = map[pos]float64{}
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)
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// GetAt returns the device scale at (x, y).
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// x and y are in device-dependent pixels.
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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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if s, ok := cache[pos{x, y}]; ok {
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return s
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}
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s := impl(x, y)
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cache[pos{x, y}] = s
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// TODO: Provide a way to invalidate the cache, or move the cache.
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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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return s
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}
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