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Add MeasureMultilineString method to Context.

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Fix #https://github.com/fogleman/gg/issues/49
This commit is contained in:
Timofey Kulin 2018-10-23 09:25:34 +03:00
parent 0e0ff3ade7
commit 16a00d1152
1 changed files with 27 additions and 0 deletions
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27
context.go
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@ -8,6 +8,7 @@ import (
"image/png" "image/png"
"io" "io"
"math" "math"
"strings"
"github.com/golang/freetype/raster" "github.com/golang/freetype/raster"
"golang.org/x/image/draw" "golang.org/x/image/draw"
@ -725,8 +726,11 @@ func (dc *Context) DrawStringAnchored(s string, x, y, ax, ay float64) {
// spacing and text alignment. // spacing and text alignment.
func (dc *Context) DrawStringWrapped(s string, x, y, ax, ay, width, lineSpacing float64, align Align) { func (dc *Context) DrawStringWrapped(s string, x, y, ax, ay, width, lineSpacing float64, align Align) {
lines := dc.WordWrap(s, width) lines := dc.WordWrap(s, width)
// sync h formula with MeasureMultilineString
h := float64(len(lines)) * dc.fontHeight * lineSpacing h := float64(len(lines)) * dc.fontHeight * lineSpacing
h -= (lineSpacing - 1) * dc.fontHeight h -= (lineSpacing - 1) * dc.fontHeight
x -= ax * width x -= ax * width
y -= ay * h y -= ay * h
switch align { switch align {
@ -746,6 +750,29 @@ func (dc *Context) DrawStringWrapped(s string, x, y, ax, ay, width, lineSpacing
} }
} }
func (dc *Context) MeasureMultilineString(s string, lineSpacing float64) (width, height float64) {
lines := strings.Split(s, "\n")
// sync h formula with DrawStringWrapped
height = float64(len(lines)) * dc.fontHeight * lineSpacing
height -= (lineSpacing - 1) * dc.fontHeight
d := &font.Drawer{
Face: dc.fontFace,
}
// max width from lines
for _, line := range lines {
adv := d.MeasureString(line)
currentWidth := float64(adv >> 6) // from gg.Context.MeasureString
if currentWidth > width {
width = currentWidth
}
}
return width, height
}
// MeasureString returns the rendered width and height of the specified text // MeasureString returns the rendered width and height of the specified text
// given the current font face. // given the current font face.
func (dc *Context) MeasureString(s string) (w, h float64) { func (dc *Context) MeasureString(s string) (w, h float64) {