Files
ofdgo/ofdgo_renderer_page_canvas.go
T
2026-09-23 17:20:25 +08:00

77 lines
2.3 KiB
Go

// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ofdgo
import (
"github.com/tdewolff/canvas"
)
// renderCanvasPage 渲染特定页面内容
// 入参: page 页面内容
// 返回: *canvas.Canvas 画布实例, error 错误信息
func (r *Renderer) renderCanvasPage(page *PageContent) (*canvas.Canvas, error) {
box, err := r.GetPageBox(page)
if err != nil {
return nil, err
}
width, height := box.W, box.H
c := canvas.New(width, height)
ctx := canvas.NewContext(c)
if err := r.renderCanvasPageToContext(ctx, page, !r.TransparentBackground); err != nil {
return nil, err
}
return c, nil
}
// renderCanvasContext 渲染页面到默认解释器上下文
// 入参: ctx 画布上下文, page 页面内容
// 返回: error 错误信息
func (r *Renderer) renderCanvasContext(ctx *canvas.Context, page *PageContent) error {
renderer := *r
renderer.decodeImages = true
return renderer.renderCanvasPageToContext(ctx, page, !r.TransparentBackground)
}
// renderCanvasPageToContext 渲染页面到指定上下文
// 入参: ctx 画布上下文, page 页面内容, drawBackground 是否绘制页面背景
// 返回: error 错误信息
func (r *Renderer) renderCanvasPageToContext(ctx *canvas.Context, page *PageContent, drawBackground bool) error {
r.renderError = nil
box, err := r.GetPageBox(page)
if err != nil {
return err
}
if r.OnPageText != nil {
renderer := *r
renderer.pageText = &PageText{}
r = &renderer
}
pageH := box.H
if drawBackground {
ctx.SetFillColor(canvas.White)
ctx.DrawPath(0, 0, canvas.Rectangle(box.W, box.H))
}
if err := r.WalkPage(page, &canvasPageVisitor{r, ctx, pageH}); err != nil {
return err
}
if r.renderError != nil {
return r.renderError
}
if r.OnPageText != nil {
r.OnPageText(page, r.pageText)
}
return nil
}