mirror of
https://github.com/unidoc/unipdf.git
synced 2025-04-27 13:48:51 +08:00
d961079c5d
* Add render package * Add text state * Add more text operators * Remove unnecessary files * Add text font * Add custom text render method * Improve text rendering method * Rename text state methods * Refactor and document context interface * Refact text begin/end operators * Fix graphics state transformations * Keep original font when doing font substitution * Take page cropbox into account * Revert to substitution font if original font measurement is 0 * Add font substitution package * Implement addition transform.Point methods * Use transform.Point in the image context package * Remove unneeded functionality from the render image package * Fix golint notices in the image rendering package * Fix go vet notices in the render package * Fix golint notices in the top-level render package * Improve render context package documentation * Document context text state struct. * Document context text font struct. * Minor logging improvements * Add license disclaimer to the render package files * Avoid using package aliases where possible * Change style of section comments * Adapt render package import style to follow the developer guide * Improve documentation for the internal matrix implementation * Update render package dependency versions * Apply crop box post render * Account for offseted media boxes * Improve metrics of rendered characters * Fix text matrix translation * Change priority of fonts used for measuring rendered characters * Skip invalid m and l operators on image rendering * Small fix for v operator * Fix rendered characters spacing issues * Refactor naming of internal render packages
107 lines
2.4 KiB
Go
107 lines
2.4 KiB
Go
/*
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* This file is subject to the terms and conditions defined in
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* file 'LICENSE.md', which is part of this source code package.
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*/
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package render
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import (
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"errors"
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"fmt"
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"image"
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"image/draw"
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"image/jpeg"
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"image/png"
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"os"
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"path/filepath"
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"strings"
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"github.com/unidoc/unipdf/v3/model"
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"github.com/unidoc/unipdf/v3/render/internal/context/imagerender"
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)
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// ImageDevice is used to render PDF pages to image targets.
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type ImageDevice struct {
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renderer
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}
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// NewImageDevice returns a new image device.
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func NewImageDevice() *ImageDevice {
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return &ImageDevice{}
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}
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// Render converts the specified PDF page into an image and returns the result.
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func (d *ImageDevice) Render(page *model.PdfPage) (image.Image, error) {
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// Get page dimensions.
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mbox, err := page.GetMediaBox()
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if err != nil {
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return nil, err
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}
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// Render page.
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width, height := mbox.Llx+mbox.Width(), mbox.Lly+mbox.Height()
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ctx := imagerender.NewContext(int(width), int(height))
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if err := d.renderPage(ctx, page); err != nil {
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return nil, err
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}
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// Apply crop box, if one exists.
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img := ctx.Image()
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if box := page.CropBox; box != nil {
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// Calculate crop bounds and crop start position.
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cropBounds := image.Rect(0, 0, int(box.Width()), int(box.Height()))
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cropStart := image.Pt(int(box.Llx), int(height-box.Ury))
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// Crop image.
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cropImg := image.NewRGBA(cropBounds)
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draw.Draw(cropImg, cropBounds, img, cropStart, draw.Src)
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img = cropImg
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}
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return img, nil
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}
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// RenderToPath converts the specified PDF page into an image and saves the
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// result at the specified location.
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func (d *ImageDevice) RenderToPath(page *model.PdfPage, outputPath string) error {
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image, err := d.Render(page)
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if err != nil {
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return err
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}
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extension := strings.ToLower(filepath.Ext(outputPath))
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if extension == "" {
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return errors.New("could not recognize output file type")
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}
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switch extension {
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case ".png":
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return savePNG(outputPath, image)
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case ".jpg", ".jpeg":
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return saveJPG(outputPath, image, 100)
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}
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return fmt.Errorf("unrecognized output file type: %s", extension)
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}
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func savePNG(path string, image image.Image) error {
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file, err := os.Create(path)
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if err != nil {
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return err
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}
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defer file.Close()
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return png.Encode(file, image)
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}
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func saveJPG(path string, image image.Image, quality int) error {
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file, err := os.Create(path)
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if err != nil {
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return err
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}
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defer file.Close()
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return jpeg.Encode(file, image, &jpeg.Options{Quality: quality})
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}
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