mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-30 01:27:26 +08:00
87 lines
3.2 KiB
Go
87 lines
3.2 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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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 ofdgo
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import (
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"image"
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"math"
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"github.com/gogpu/gg"
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)
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// ggNativeImage 判断GG最近邻采样与公共高质量采样是否等价
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// 仅接受整数像素平移及不会重复预乘的八位图片，缩放、错切和旋转沿用公共路径
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// 入参: src 源像素, matrix 像素变换
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// 返回: bool 是否可使用原生图片
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func ggNativeImage(src image.Image, matrix RasterMatrix) bool {
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if matrix[0] != 1 || matrix[1] != 0 || matrix[2] != 0 || matrix[3] != 1 ||
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!finite(matrix[4]) || !finite(matrix[5]) || matrix[4] != math.Trunc(matrix[4]) || matrix[5] != math.Trunc(matrix[5]) || src.Bounds().Empty() {
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return false
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}
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switch src := src.(type) {
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case *image.NRGBA, *image.Gray:
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return true
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case *image.RGBA:
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return src.Opaque()
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}
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return false
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}
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// ggPrepareImage 复用GG图片采样器和裁剪，不能等价采样时保留公共图像指令
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// 工厂方法只构造采样器，不创建上下文设备或调用可能隐藏错误的DrawImageEx
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// 入参: page 页面, command 图片指令, masks 裁剪缓存, images 图片适配缓存
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// 返回: ggRasterCommand 预编译图片, error 裁剪错误
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func ggPrepareImage(page *RasterPage, command RasterCommand, masks *renderCache[[32]byte, *image.Alpha], images *renderCache[image.Image, *gg.ImageBuf]) (ggRasterCommand, error) {
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result := ggRasterCommand{command: command}
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_, height, _ := page.PixelSize()
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matrix := page.PixelTransform(command.Transform, height)
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src := imagePixelSource(command.Image)
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if !ggNativeImage(src, matrix) {
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return result, nil
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}
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buffer, ok := images.get(src)
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if !ok {
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buffer = gg.ImageBufFromImage(src)
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images.put(src, buffer, src.Bounds().Dx()*src.Bounds().Dy()*4+256)
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}
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bounds := src.Bounds()
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x, y := matrix[4]+float64(bounds.Min.X), matrix[5]+float64(bounds.Min.Y)
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pattern := new(gg.Context).CreateImagePattern(buffer, 0, 0, bounds.Dx(), bounds.Dy()).(*gg.ImagePattern)
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pattern.SetClamp(true)
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pattern.SetTransform(gg.Translate(x, y))
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paint := gg.NewPaint()
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paint.SetFillBrush(gg.BrushFromPattern(pattern))
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if command.Clip != nil {
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mask, err := rasterClipMask(GGBackend{}, page, command.Clip, masks)
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if err != nil {
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return result, err
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}
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if mask.Rect.Empty() {
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result.path, result.paint = gg.NewPath(), paint
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return result, nil
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}
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paint.ClipMask, paint.ClipMaskW, paint.ClipMaskH = mask.Pix, mask.Stride, mask.Rect.Dy()
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paint.ClipMaskX, paint.ClipMaskY = mask.Rect.Min.X, mask.Rect.Min.Y
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}
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path := gg.NewPath()
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path.MoveTo(x, y)
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path.LineTo(x+float64(bounds.Dx()), y)
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path.LineTo(x+float64(bounds.Dx()), y+float64(bounds.Dy()))
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path.LineTo(x, y+float64(bounds.Dy()))
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path.Close()
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result.path, result.paint = path, paint
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return result, nil
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}
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