4a5cc2dd26
Add an "alignx" option to the images.Text to control whether the value of the "x" option is the left border of the text (current behaviour), the center of each line or the right border. Fixes #10849
142 lines
3.3 KiB
Go
142 lines
3.3 KiB
Go
// Copyright 2021 The Hugo Authors. All rights reserved.
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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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// 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 images
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import (
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"image"
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"image/color"
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"image/draw"
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"io"
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"strings"
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"github.com/disintegration/gift"
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"github.com/gohugoio/hugo/common/hugio"
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"golang.org/x/image/font"
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"golang.org/x/image/font/gofont/goregular"
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"golang.org/x/image/font/opentype"
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"golang.org/x/image/math/fixed"
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)
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var _ gift.Filter = (*textFilter)(nil)
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type textFilter struct {
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text string
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color color.Color
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x, y int
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alignx string
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size float64
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linespacing int
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fontSource hugio.ReadSeekCloserProvider
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}
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func (f textFilter) Draw(dst draw.Image, src image.Image, options *gift.Options) {
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// Load and parse font
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ttf := goregular.TTF
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if f.fontSource != nil {
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rs, err := f.fontSource.ReadSeekCloser()
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if err != nil {
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panic(err)
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}
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defer rs.Close()
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ttf, err = io.ReadAll(rs)
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if err != nil {
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panic(err)
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}
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}
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otf, err := opentype.Parse(ttf)
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if err != nil {
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panic(err)
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}
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// Set font options
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face, err := opentype.NewFace(otf, &opentype.FaceOptions{
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Size: f.size,
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DPI: 72,
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Hinting: font.HintingNone,
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})
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if err != nil {
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panic(err)
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}
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d := font.Drawer{
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Dst: dst,
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Src: image.NewUniform(f.color),
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Face: face,
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}
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gift.New().Draw(dst, src)
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maxWidth := dst.Bounds().Dx() - 20
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var availableWidth int
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switch f.alignx {
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case "right":
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availableWidth = f.x
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case "center":
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availableWidth = min((maxWidth-f.x), f.x) * 2
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case "left":
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availableWidth = maxWidth - f.x
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}
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fontHeight := face.Metrics().Ascent.Ceil()
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// Calculate lines, consider and include linebreaks
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finalLines := []string{}
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f.text = strings.ReplaceAll(f.text, "\r", "")
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for _, line := range strings.Split(f.text, "\n") {
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currentLine := ""
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// Break each line at the maximum width.
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for _, str := range strings.Fields(line) {
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fieldStrWidth := font.MeasureString(face, str)
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currentLineStrWidth := font.MeasureString(face, currentLine)
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if (currentLineStrWidth.Ceil() + fieldStrWidth.Ceil()) >= availableWidth {
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finalLines = append(finalLines, currentLine)
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currentLine = ""
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}
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currentLine += str + " "
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}
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finalLines = append(finalLines, currentLine)
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}
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// Correct y position based on font and size
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f.y = f.y + fontHeight
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// Start position
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y := f.y
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// Draw text line by line
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for _, line := range finalLines {
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line = strings.TrimSpace(line)
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strWidth := font.MeasureString(face, line)
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var x int
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switch f.alignx {
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case "right":
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x = f.x - strWidth.Ceil()
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case "center":
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x = f.x - (strWidth.Ceil() / 2)
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case "left":
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x = f.x
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}
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d.Dot = fixed.P(x, y)
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d.DrawString(line)
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y = y + fontHeight + f.linespacing
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}
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}
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func (f textFilter) Bounds(srcBounds image.Rectangle) image.Rectangle {
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return image.Rect(0, 0, srcBounds.Dx(), srcBounds.Dy())
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}
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