mirror of
https://github.com/hajimehoshi/ebiten.git
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85 lines
2.1 KiB
Go
85 lines
2.1 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 driver
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import (
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"fmt"
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)
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type CompositeMode int
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const (
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CompositeModeUnknown CompositeMode = iota - 1
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CompositeModeSourceOver // This value must be 0 (= initial value)
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CompositeModeClear
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CompositeModeCopy
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CompositeModeDestination
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CompositeModeDestinationOver
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CompositeModeSourceIn
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CompositeModeDestinationIn
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CompositeModeSourceOut
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CompositeModeDestinationOut
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CompositeModeSourceAtop
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CompositeModeDestinationAtop
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CompositeModeXor
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CompositeModeLighter
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CompositeModeMax = CompositeModeLighter
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)
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type Operation int
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const (
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Zero Operation = iota
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One
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SrcAlpha
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DstAlpha
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OneMinusSrcAlpha
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OneMinusDstAlpha
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)
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func (c CompositeMode) Operations() (src Operation, dst Operation) {
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switch c {
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case CompositeModeSourceOver:
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return One, OneMinusSrcAlpha
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case CompositeModeClear:
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return Zero, Zero
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case CompositeModeCopy:
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return One, Zero
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case CompositeModeDestination:
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return Zero, One
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case CompositeModeDestinationOver:
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return OneMinusDstAlpha, One
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case CompositeModeSourceIn:
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return DstAlpha, Zero
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case CompositeModeDestinationIn:
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return Zero, SrcAlpha
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case CompositeModeSourceOut:
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return OneMinusDstAlpha, Zero
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case CompositeModeDestinationOut:
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return Zero, OneMinusSrcAlpha
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case CompositeModeSourceAtop:
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return DstAlpha, OneMinusSrcAlpha
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case CompositeModeDestinationAtop:
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return OneMinusDstAlpha, SrcAlpha
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case CompositeModeXor:
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return OneMinusDstAlpha, OneMinusSrcAlpha
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case CompositeModeLighter:
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return One, One
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default:
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panic(fmt.Sprintf("graphics: invalid composite mode: %d", c))
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}
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}
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