mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-30 01:27:26 +08:00
96 lines
3.4 KiB
Go
96 lines
3.4 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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"math"
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"github.com/tdewolff/canvas"
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)
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// parseFillPaint 将公共画刷转换为Canvas对象
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// 入参: fillColor 填充颜色节点, x X坐标, y Y坐标, pageH 页面高度
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// 返回: any 填充画刷
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func (r *Renderer) parseFillPaint(fillColor *FillColor, x, y, pageH float64) any {
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paint := r.ResolvePaint(fillColor)
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switch paint.Kind {
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case PaintNone, PaintPattern:
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return nil
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case PaintLinear, PaintRadial:
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return canvasShading(paint, x, y, pageH)
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default:
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return paint.Color
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}
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}
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// parseStrokePaint 解析勾边画刷
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// 入参: strokeColor 勾边颜色节点, x X坐标, y Y坐标, pageH 页面高度
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// 返回: any 勾边画刷
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func (r *Renderer) parseStrokePaint(strokeColor *StrokeColor, x, y, pageH float64) any {
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return r.parseFillPaint((*FillColor)(strokeColor), x, y, pageH)
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}
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// canvasGradient 将公共颜色节点转换为Canvas渐变
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// 入参: stops 渐变分段
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// 返回: canvas.Grad 渐变分段
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func canvasGradient(stops []ColorStop) canvas.Grad {
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var gradient canvas.Grad
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for _, stop := range stops {
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gradient.Add(stop.Offset, stop.Color)
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}
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return gradient
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}
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// canvasShading 转换坐标与椭圆渐变变换，不重新解析OFD样式
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// 入参: paint 公共渐变画刷, x X坐标, y Y坐标, pageH 页面高度
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// 返回: *shdPaint Canvas渐变画刷
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func canvasShading(paint Paint, x, y, pageH float64) *shdPaint {
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source := paint.Gradient
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gradient := canvasGradient(source.Stops)
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start := canvas.Point{X: x + source.Start.X, Y: pageH - y - source.Start.Y}
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end := canvas.Point{X: x + source.End.X, Y: pageH - y - source.End.Y}
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if paint.Kind == PaintLinear {
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return newShdPaint(gradient.ToLinear(start, end), source.Extend, source.MapType, source.MapUnit)
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}
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result := newShdPaint(gradient.ToRadial(start, source.StartRadius, end, source.EndRadius), source.Extend, source.MapType, source.MapUnit)
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if e := source.Eccentricity; 0 < e && e < 1 {
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result.view = canvas.Identity.Translate(start.X, start.Y).Rotate(-source.Angle).Scale(1, math.Sqrt(1-e*e)).Translate(-start.X, -start.Y)
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result.gradient = gradient.ToRadial(start, source.StartRadius, result.view.Inv().Dot(end), source.EndRadius)
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}
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return result
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}
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// axialShdClip 获取轴向渐变的延伸裁剪区域
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// 入参: gradient 轴向渐变, extend 延伸方向, bounds 可见区域
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// 返回: *canvas.Path 裁剪区域
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func axialShdClip(gradient *canvas.LinearGradient, extend int, bounds canvas.Rect) *canvas.Path {
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if extend == 3 {
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return nil
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}
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d := gradient.End.Sub(gradient.Start)
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axis := canvas.Matrix{{d.X, -d.Y, gradient.Start.X}, {d.Y, d.X, gradient.Start.Y}}
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area := bounds.Transform(axis.Inv())
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if extend&1 == 0 {
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area.X0 = math.Max(area.X0, 0)
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}
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if extend&2 == 0 {
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area.X1 = math.Min(area.X1, 1)
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}
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if area.X1 <= area.X0 {
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return &canvas.Path{}
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}
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return area.ToPath().Transform(axis)
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}
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