mirror of
https://github.com/hajimehoshi/ebiten.git
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62 lines
1.9 KiB
Go
62 lines
1.9 KiB
Go
// Copyright 2017 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 ebitenutil
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import (
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"image"
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"image/color"
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"math"
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"github.com/hajimehoshi/ebiten/v2"
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)
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var (
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emptyImage = ebiten.NewImage(3, 3)
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emptySubImage = emptyImage.SubImage(image.Rect(1, 1, 2, 2)).(*ebiten.Image)
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)
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func init() {
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emptyImage.Fill(color.White)
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}
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// DrawLine draws a line segment on the given destination dst.
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//
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// DrawLine is intended to be used mainly for debugging or prototyping purpose.
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func DrawLine(dst *ebiten.Image, x1, y1, x2, y2 float64, clr color.Color) {
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length := math.Hypot(x2-x1, y2-y1)
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op := &ebiten.DrawImageOptions{}
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op.GeoM.Scale(length, 1)
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op.GeoM.Rotate(math.Atan2(y2-y1, x2-x1))
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op.GeoM.Translate(x1, y1)
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op.ColorM.ScaleWithColor(clr)
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// Filter must be 'nearest' filter (default).
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// Linear filtering would make edges blurred.
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dst.DrawImage(emptySubImage, op)
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}
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// DrawRect draws a rectangle on the given destination dst.
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//
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// DrawRect is intended to be used mainly for debugging or prototyping purpose.
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func DrawRect(dst *ebiten.Image, x, y, width, height float64, clr color.Color) {
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op := &ebiten.DrawImageOptions{}
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op.GeoM.Scale(width, height)
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op.GeoM.Translate(x, y)
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op.ColorM.ScaleWithColor(clr)
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// Filter must be 'nearest' filter (default).
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// Linear filtering would make edges blurred.
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dst.DrawImage(emptyImage.SubImage(image.Rect(1, 1, 2, 2)).(*ebiten.Image), op)
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}
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