mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-30 01:27:26 +08:00
259 lines
8.2 KiB
Go
259 lines
8.2 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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"fmt"
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"image"
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"image/color"
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"sync"
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"github.com/gogpu/gg"
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)
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// GGBackend 提供字体、页面编译和CPU绘制，不注册全局GPU设备或隐式切换后端
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// StrokeGeometry用于GG暂不能准确处理的尖角连接、闭合或曲线虚线及亚像素渐变描边，未配置时返回能力错误
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type GGBackend struct{ StrokeGeometry GeometryBackend }
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// Name 返回后端标识
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// 返回: string 后端标识
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func (GGBackend) Name() string { return "gg" }
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// Prepare 将路径、样式和裁剪准备为固定DPI的GG场景
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// 入参: page 只读页面
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// 返回: RasterScene 可重复绘制场景, error 准备错误
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func (b GGBackend) Prepare(page *RasterPage) (RasterScene, error) {
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return b.prepareShared(page, nil)
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}
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// PrepareReuse 复用同配置GG场景的派生数据，其他后端场景不参与复用
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// 入参: page 新页面, previous 前次场景
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// 返回: RasterScene 独立快照, error 准备错误
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func (b GGBackend) PrepareReuse(page *RasterPage, previous RasterScene) (RasterScene, error) {
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scene, _ := previous.(*ggRasterScene)
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return b.prepareShared(page, scene)
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}
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// prepareShared 为新快照复用同配置的派生缓存，不改变旧快照
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// 入参: page 新页面, previous 前次同渲染器场景
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// 返回: *ggRasterScene 独立场景, error 准备错误
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func (b GGBackend) prepareShared(page *RasterPage, previous *ggRasterScene) (*ggRasterScene, error) {
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scene := &ggRasterScene{
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mu: &sync.Mutex{},
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backend: b,
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masks: &renderCache[[32]byte, *image.Alpha]{limit: 16 << 20},
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prepared: &renderCache[[32]byte, ggRasterCommand]{limit: 16 << 20},
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images: &renderCache[image.Image, *gg.ImageBuf]{limit: 16 << 20},
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}
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if previous != nil && sameBackend(b.StrokeGeometry, previous.backend.StrokeGeometry) {
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scene.mu, scene.masks, scene.prepared, scene.images = previous.mu, previous.masks, previous.prepared, previous.images
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}
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if err := scene.Update(page); err != nil {
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return nil, err
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}
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return scene, nil
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}
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// Update 按内容复用未编辑的指令，成功后原子替换场景快照
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// 入参: page 编辑后的只读页面
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// 返回: error 准备错误，失败时保留原场景
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func (scene *ggRasterScene) Update(page *RasterPage) error {
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scene.mu.Lock()
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defer scene.mu.Unlock()
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w, h, err := page.PixelSize()
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if err != nil {
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return err
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}
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page = cloneRasterPage(page)
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commands := make([]ggRasterCommand, 0, len(page.Commands))
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for i, cmd := range page.Commands {
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if cmd.Image != nil {
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cmd.Stroke = nil
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prepared, err := ggPrepareImage(page, cmd, scene.masks, scene.images)
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if err != nil {
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return fmt.Errorf("gg command %d: %w", i, err)
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}
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commands = append(commands, prepared)
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continue
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}
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key := rasterCommandKey(page, cmd)
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if prepared, ok := scene.prepared.get(key); ok {
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commands = append(commands, prepared)
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continue
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}
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if cmd.Stroke != nil && !ggNativeStroke(cmd, page.DPI/25.4) {
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cmd, err = scene.backend.expandStroke(cmd)
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if err != nil {
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return fmt.Errorf("gg command %d: %w", i, err)
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}
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}
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m := page.PixelTransform(cmd.Transform, h)
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path := gg.NewPath()
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for _, s := range cmd.Path {
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end, c1, c2 := m.Apply(s.End), m.Apply(s.Control1), m.Apply(s.Control2)
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switch s.Verb {
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case RasterMove:
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path.MoveTo(end.X, end.Y)
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case RasterLine:
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path.LineTo(end.X, end.Y)
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case RasterQuad:
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path.QuadraticTo(c1.X, c1.Y, end.X, end.Y)
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case RasterCubic:
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path.CubicTo(c1.X, c1.Y, c2.X, c2.Y, end.X, end.Y)
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case RasterClose:
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path.Close()
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default:
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return fmt.Errorf("gg command %d: unsupported path verb %d", i, s.Verb)
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}
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}
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paint := gg.NewPaint()
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paint.SetFillBrush(gg.SolidBrush{Color: ggRGBA(cmd.Paint.Color)})
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if g := cmd.Paint.Gradient; g != nil {
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brush, err := ggGradientBrush(g, m)
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if err != nil {
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return fmt.Errorf("gg command %d: %w", i, err)
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}
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paint.SetFillBrush(brush)
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}
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if cmd.EvenOdd && cmd.Stroke == nil {
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paint.FillRule = gg.FillRuleEvenOdd
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}
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if cmd.Clip != nil {
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mask, err := rasterClipMask(GGBackend{}, page, cmd.Clip, scene.masks)
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if err != nil {
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return err
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}
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if mask.Rect.Empty() {
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continue
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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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if cmd.Stroke != nil {
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style, err := ggStroke(*cmd.Stroke, page.DPI/25.4)
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if err != nil {
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return err
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}
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paint.SetStroke(style)
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paint.SetStrokeBrush(paint.FillBrush())
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}
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prepared := ggRasterCommand{command: cmd, path: path, paint: paint}
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scene.prepared.put(key, prepared, rasterCommandCost(cmd)+len(paint.ClipMask))
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commands = append(commands, prepared)
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}
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scene.page, scene.width, scene.height, scene.commands = page, w, h, commands
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return nil
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}
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// ggRasterCommand 保存已转换的像素路径和样式
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type ggRasterCommand struct {
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command RasterCommand
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path *gg.Path
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paint *gg.Paint
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}
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// ggRasterScene 复用路径和局部裁剪，串行保护掩码缓存
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type ggRasterScene struct {
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mu *sync.Mutex
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backend GGBackend
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page *RasterPage
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width, height int
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commands []ggRasterCommand
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masks *renderCache[[32]byte, *image.Alpha]
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prepared *renderCache[[32]byte, ggRasterCommand]
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images *renderCache[image.Image, *gg.ImageBuf]
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}
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// Render 绘制独立像素缓冲，不累积上次内容
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// 返回: image.Image 图像, error 绘制错误
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func (s *ggRasterScene) Render() (image.Image, error) {
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s.mu.Lock()
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defer s.mu.Unlock()
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pixmap := gg.NewPixmap(s.width, s.height)
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img := pixmap.ImageView()
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raster := gg.NewSoftwareRenderer(s.width, s.height)
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for i, cmd := range s.commands {
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var err error
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switch {
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case cmd.command.Image != nil && cmd.path == nil:
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err = drawRasterImageCommand(GGBackend{}, s.page, img, imagePixelSource(cmd.command.Image), cmd.command, s.masks)
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case cmd.command.Stroke != nil:
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err = raster.Stroke(pixmap, cmd.path, cmd.paint)
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default:
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err = raster.Fill(pixmap, cmd.path, cmd.paint)
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}
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if err != nil {
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return nil, fmt.Errorf("gg command %d: %w", i, err)
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}
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}
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return img, nil
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}
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// Render 准备并绘制页面，重复绘制可使用Prepare复用场景
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// 入参: page 只读页面
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// 返回: image.Image 图像, error 绘制错误
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func (b GGBackend) Render(page *RasterPage) (image.Image, error) {
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scene, err := b.Prepare(page)
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if err != nil {
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return nil, err
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}
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return scene.Render()
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}
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// ggStroke 将页面毫米样式转换为GG像素描边，虚线与线宽同步换算
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// 入参: options 描边样式, scale 每毫米像素数
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// 返回: gg.Stroke 像素样式, error 样式错误
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func ggStroke(options StrokeOptions, scale float64) (gg.Stroke, error) {
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if err := validateStroke(options); err != nil {
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return gg.Stroke{}, err
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}
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style := gg.DefaultStroke().WithWidth(options.Width * scale)
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style.MiterLimit = options.MiterLimit
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if style.MiterLimit == 0 {
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style.MiterLimit = defaultMiterLimit
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}
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switch options.Cap {
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case "Round":
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style.Cap = gg.LineCapRound
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case "Square":
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style.Cap = gg.LineCapSquare
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}
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switch options.Join {
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case "Round":
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style.Join = gg.LineJoinRound
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case "Bevel":
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style.Join = gg.LineJoinBevel
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}
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if len(options.Dashes) > 0 {
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dashes := make([]float64, len(options.Dashes))
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for i, value := range options.Dashes {
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dashes[i] = value * scale
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}
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style = style.WithDashPattern(dashes...).WithDashOffset(options.DashOffset * scale)
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}
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return style, nil
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}
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// ggRGBA 将标准库预乘颜色转换为gg的非预乘颜色
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// 入参: c 预乘颜色
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// 返回: gg.RGBA 非预乘颜色
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func ggRGBA(c color.RGBA) gg.RGBA {
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if c.A == 0 {
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return gg.Transparent
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}
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a := float64(c.A)
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return gg.RGBA{R: float64(c.R) / a, G: float64(c.G) / a, B: float64(c.B) / a, A: a / 255}
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}
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