Moved generic text functions to draw2dbase

draw2dbase/stack_gc.go

@@ -4,12 +4,17 @@
 package draw2dbase
 
 import (
+	"errors"
 	"image"
 	"image/color"
+	"log"
+	"math"
 
 	"github.com/llgcode/draw2d"
 
 	"github.com/golang/freetype/truetype"
+	"golang.org/x/image/font"
+	"golang.org/x/image/math/fixed"
 )
 
 var DefaultFontData = draw2d.FontData{Name: "luxi", Family: draw2d.FontFamilySans, Style: draw2d.FontStyleNormal}
@@ -36,6 +41,8 @@ type ContextStack struct {
 	// fontSize and dpi are used to calculate scale. scale is the number of
 	// 26.6 fixed point units in 1 em.
 	Scale float64
+	glyphBuf         *truetype.GlyphBuf
+	DPI		int
 
 	Previous *ContextStack
 }
@@ -56,6 +63,8 @@ func NewStackGraphicContext() *StackGraphicContext {
 	gc.Current.Join = draw2d.RoundJoin
 	gc.Current.FontSize = 10
 	gc.Current.FontData = DefaultFontData
+	gc.Current.glyphBuf = &truetype.GlyphBuf{}
+	gc.Current.DPI = 92
 	return gc
 }
 
@@ -112,8 +121,10 @@ func (gc *StackGraphicContext) SetLineDash(dash []float64, dashOffset float64) {
 	gc.Current.DashOffset = dashOffset
 }
 
+// SetFontSize sets the font size in points (as in ``a 12 point font'').
 func (gc *StackGraphicContext) SetFontSize(fontSize float64) {
 	gc.Current.FontSize = fontSize
+	gc.recalc()
 }
 
 func (gc *StackGraphicContext) GetFontSize() float64 {
@@ -179,6 +190,8 @@ func (gc *StackGraphicContext) Save() {
 	context.Path = gc.Current.Path.Copy()
 	context.Font = gc.Current.Font
 	context.Scale = gc.Current.Scale
+	context.glyphBuf = gc.Current.glyphBuf
+	context.DPI = gc.Current.DPI
 	copy(context.Tr[:], gc.Current.Tr[:])
 	context.Previous = gc.Current
 	gc.Current = context
@@ -191,3 +204,117 @@ func (gc *StackGraphicContext) Restore() {
 		oldContext.Previous = nil
 	}
 }
+
+func (gc *StackGraphicContext) loadCurrentFont() (*truetype.Font, error) {
+	font := draw2d.GetFont(gc.Current.FontData)
+	if font == nil {
+		font = draw2d.GetFont(DefaultFontData)
+	}
+	if font == nil {
+		return nil, errors.New("No font set, and no default font available.")
+	}
+	gc.SetFont(font)
+	gc.SetFontSize(gc.Current.FontSize)
+	return font, nil
+}
+
+func (gc *StackGraphicContext) drawGlyph(glyph truetype.Index, dx, dy float64) error {
+	if err := gc.Current.glyphBuf.Load(gc.Current.Font, fixed.Int26_6(gc.Current.Scale), glyph, font.HintingNone); err != nil {
+		return err
+	}
+	e0 := 0
+	for _, e1 := range gc.Current.glyphBuf.Ends {
+		DrawContour(gc, gc.Current.glyphBuf.Points[e0:e1], dx, dy)
+		e0 = e1
+	}
+	return nil
+}
+
+// CreateStringPath creates a path from the string s at x, y, and returns the string width.
+// The text is placed so that the left edge of the em square of the first character of s
+// and the baseline intersect at x, y. The majority of the affected pixels will be
+// above and to the right of the point, but some may be below or to the left.
+// For example, drawing a string that starts with a 'J' in an italic font may
+// affect pixels below and left of the point.
+func (gc *StackGraphicContext) CreateStringPath(s string, x, y float64) float64 {
+	f, err := gc.loadCurrentFont()
+	if err != nil {
+		log.Println(err)
+		return 0.0
+	}
+	startx := x
+	prev, hasPrev := truetype.Index(0), false
+	for _, rune := range s {
+		index := f.Index(rune)
+		if hasPrev {
+			x += fUnitsToFloat64(f.Kern(fixed.Int26_6(gc.Current.Scale), prev, index))
+		}
+		err := gc.drawGlyph(index, x, y)
+		if err != nil {
+			log.Println(err)
+			return startx - x
+		}
+		x += fUnitsToFloat64(f.HMetric(fixed.Int26_6(gc.Current.Scale), index).AdvanceWidth)
+		prev, hasPrev = index, true
+	}
+	return x - startx
+}
+
+// GetStringBounds returns the approximate pixel bounds of the string s at x, y.
+// The the left edge of the em square of the first character of s
+// and the baseline intersect at 0, 0 in the returned coordinates.
+// Therefore the top and left coordinates may well be negative.
+func (gc *StackGraphicContext) GetStringBounds(s string) (left, top, right, bottom float64) {
+	f, err := gc.loadCurrentFont()
+	if err != nil {
+		log.Println(err)
+		return 0, 0, 0, 0
+	}
+	top, left, bottom, right = 10e6, 10e6, -10e6, -10e6
+	cursor := 0.0
+	prev, hasPrev := truetype.Index(0), false
+	for _, rune := range s {
+		index := f.Index(rune)
+		if hasPrev {
+			cursor += fUnitsToFloat64(f.Kern(fixed.Int26_6(gc.Current.Scale), prev, index))
+		}
+		if err := gc.Current.glyphBuf.Load(gc.Current.Font, fixed.Int26_6(gc.Current.Scale), index, font.HintingNone); err != nil {
+			log.Println(err)
+			return 0, 0, 0, 0
+		}
+		e0 := 0
+		for _, e1 := range gc.Current.glyphBuf.Ends {
+			ps := gc.Current.glyphBuf.Points[e0:e1]
+			for _, p := range ps {
+				x, y := pointToF64Point(p)
+				top = math.Min(top, y)
+				bottom = math.Max(bottom, y)
+				left = math.Min(left, x+cursor)
+				right = math.Max(right, x+cursor)
+			}
+		}
+		cursor += fUnitsToFloat64(f.HMetric(fixed.Int26_6(gc.Current.Scale), index).AdvanceWidth)
+		prev, hasPrev = index, true
+	}
+	return left, top, right, bottom
+}
+
+// recalc recalculates scale and bounds values from the font size, screen
+// resolution and font metrics, and invalidates the glyph cache.
+func (gc *StackGraphicContext) recalc() {
+	gc.Current.Scale = gc.Current.FontSize * float64(gc.Current.DPI) * (64.0 / 72.0)
+}
+
+func (gc *StackGraphicContext) SetDPI(dpi int) {
+	gc.Current.DPI = dpi
+	gc.recalc()
+}
+
+// SetFont sets the font used to draw text.
+func (gc *StackGraphicContext) SetFont(font *truetype.Font) {
+	gc.Current.Font = font
+}
+
+func (gc *StackGraphicContext) GetDPI() int {
+	return gc.Current.DPI
+}

draw2dbase/text.go

@@ -1,4 +1,4 @@
-package draw2dgl
+package draw2dbase
 
 import (
 	"github.com/golang/freetype/truetype"

draw2dgl/gc.go

@@ -1,23 +1,16 @@
 package draw2dgl
 
 import (
-	"errors"
 	"image"
 	"image/color"
 	"image/draw"
-	"log"
-	"math"
 	"runtime"
 
 	"github.com/go-gl/gl/v2.1/gl"
 	"github.com/golang/freetype/raster"
-	"github.com/golang/freetype/truetype"
 	"github.com/llgcode/draw2d"
 	"github.com/llgcode/draw2d/draw2dbase"
 	"github.com/llgcode/draw2d/draw2dimg"
-
-	"golang.org/x/image/font"
-	"golang.org/x/image/math/fixed"
 )
 
 func init() {
@@ -125,8 +118,6 @@ type GraphicContext struct {
 	painter          *Painter
 	fillRasterizer   *raster.Rasterizer
 	strokeRasterizer *raster.Rasterizer
-	glyphBuf         *truetype.GlyphBuf
-	DPI		int
 }
 
 // NewGraphicContext creates a new Graphic context from an image.
@@ -136,112 +127,16 @@ func NewGraphicContext(width, height int) *GraphicContext {
 		NewPainter(),
 		raster.NewRasterizer(width, height),
 		raster.NewRasterizer(width, height),
-		&truetype.GlyphBuf{},
-		92,
 	}
 	return gc
 }
 
-func (gc *GraphicContext) loadCurrentFont() (*truetype.Font, error) {
-	font := draw2d.GetFont(gc.Current.FontData)
-	if font == nil {
-		font = draw2d.GetFont(draw2dbase.DefaultFontData)
-	}
-	if font == nil {
-		return nil, errors.New("No font set, and no default font available.")
-	}
-	gc.SetFont(font)
-	gc.SetFontSize(gc.Current.FontSize)
-	return font, nil
-}
-
-func (gc *GraphicContext) drawGlyph(glyph truetype.Index, dx, dy float64) error {
-	if err := gc.glyphBuf.Load(gc.Current.Font, fixed.Int26_6(gc.Current.Scale), glyph, font.HintingNone); err != nil {
-		return err
-	}
-	e0 := 0
-	for _, e1 := range gc.glyphBuf.Ends {
-		DrawContour(gc, gc.glyphBuf.Points[e0:e1], dx, dy)
-		e0 = e1
-	}
-	return nil
-}
-
-// CreateStringPath creates a path from the string s at x, y, and returns the string width.
-// The text is placed so that the left edge of the em square of the first character of s
-// and the baseline intersect at x, y. The majority of the affected pixels will be
-// above and to the right of the point, but some may be below or to the left.
-// For example, drawing a string that starts with a 'J' in an italic font may
-// affect pixels below and left of the point.
-func (gc *GraphicContext) CreateStringPath(s string, x, y float64) float64 {
-	f, err := gc.loadCurrentFont()
-	if err != nil {
-		log.Println(err)
-		return 0.0
-	}
-	startx := x
-	prev, hasPrev := truetype.Index(0), false
-	for _, rune := range s {
-		index := f.Index(rune)
-		if hasPrev {
-			x += fUnitsToFloat64(f.Kern(fixed.Int26_6(gc.Current.Scale), prev, index))
-		}
-		err := gc.drawGlyph(index, x, y)
-		if err != nil {
-			log.Println(err)
-			return startx - x
-		}
-		x += fUnitsToFloat64(f.HMetric(fixed.Int26_6(gc.Current.Scale), index).AdvanceWidth)
-		prev, hasPrev = index, true
-	}
-	return x - startx
-}
-
 func (gc *GraphicContext) FillStringAt(text string, x, y float64) (width float64) {
 	width = gc.CreateStringPath(text, x, y)
 	gc.Fill()
 	return width
 }
 
-// GetStringBounds returns the approximate pixel bounds of the string s at x, y.
-// The the left edge of the em square of the first character of s
-// and the baseline intersect at 0, 0 in the returned coordinates.
-// Therefore the top and left coordinates may well be negative.
-func (gc *GraphicContext) GetStringBounds(s string) (left, top, right, bottom float64) {
-	f, err := gc.loadCurrentFont()
-	if err != nil {
-		log.Println(err)
-		return 0, 0, 0, 0
-	}
-	top, left, bottom, right = 10e6, 10e6, -10e6, -10e6
-	cursor := 0.0
-	prev, hasPrev := truetype.Index(0), false
-	for _, rune := range s {
-		index := f.Index(rune)
-		if hasPrev {
-			cursor += fUnitsToFloat64(f.Kern(fixed.Int26_6(gc.Current.Scale), prev, index))
-		}
-		if err := gc.glyphBuf.Load(gc.Current.Font, fixed.Int26_6(gc.Current.Scale), index, font.HintingNone); err != nil {
-			log.Println(err)
-			return 0, 0, 0, 0
-		}
-		e0 := 0
-		for _, e1 := range gc.glyphBuf.Ends {
-			ps := gc.glyphBuf.Points[e0:e1]
-			for _, p := range ps {
-				x, y := pointToF64Point(p)
-				top = math.Min(top, y)
-				bottom = math.Max(bottom, y)
-				left = math.Min(left, x+cursor)
-				right = math.Max(right, x+cursor)
-			}
-		}
-		cursor += fUnitsToFloat64(f.HMetric(fixed.Int26_6(gc.Current.Scale), index).AdvanceWidth)
-		prev, hasPrev = index, true
-	}
-	return left, top, right, bottom
-}
-
 func (gc *GraphicContext) StrokeString(text string) (width float64) {
 	return gc.StrokeStringAt(text, 0, 0)
 }
@@ -252,32 +147,6 @@ func (gc *GraphicContext) StrokeStringAt(text string, x, y float64) (width float
 	return width
 }
 
-// recalc recalculates scale and bounds values from the font size, screen
-// resolution and font metrics, and invalidates the glyph cache.
-func (gc *GraphicContext) recalc() {
-	gc.Current.Scale = gc.Current.FontSize * float64(gc.DPI) * (64.0 / 72.0)
-}
-
-func (gc *GraphicContext) SetDPI(dpi int) {
-	gc.DPI = dpi
-	gc.recalc()
-}
-
-// SetFont sets the font used to draw text.
-func (gc *GraphicContext) SetFont(font *truetype.Font) {
-	gc.Current.Font = font
-}
-
-// SetFontSize sets the font size in points (as in ``a 12 point font'').
-func (gc *GraphicContext) SetFontSize(fontSize float64) {
-	gc.Current.FontSize = fontSize
-	gc.recalc()
-}
-
-func (gc *GraphicContext) GetDPI() int {
-	return gc.DPI
-}
-
 //TODO
 func (gc *GraphicContext) Clear() {
 	panic("not implemented")

draw2dimg/ftgc.go

@@ -4,22 +4,15 @@
 package draw2dimg
 
 import (
-	"errors"
 	"image"
 	"image/color"
-	"log"
-	"math"
-
 	"github.com/llgcode/draw2d"
 	"github.com/llgcode/draw2d/draw2dbase"
 
 	"github.com/golang/freetype/raster"
-	"github.com/golang/freetype/truetype"
 
 	"golang.org/x/image/draw"
-	"golang.org/x/image/font"
 	"golang.org/x/image/math/f64"
-	"golang.org/x/image/math/fixed"
 )
 
 // Painter implements the freetype raster.Painter and has a SetColor method like the RGBAPainter
@@ -35,8 +28,6 @@ type GraphicContext struct {
 	painter          Painter
 	fillRasterizer   *raster.Rasterizer
 	strokeRasterizer *raster.Rasterizer
-	glyphBuf         *truetype.GlyphBuf
-	DPI              int
 }
 
 // ImageFilter defines the type of filter to use
@@ -67,24 +58,16 @@ func NewGraphicContext(img draw.Image) *GraphicContext {
 // NewGraphicContextWithPainter creates a new Graphic context from an image and a Painter (see Freetype-go)
 func NewGraphicContextWithPainter(img draw.Image, painter Painter) *GraphicContext {
 	width, height := img.Bounds().Dx(), img.Bounds().Dy()
-	dpi := 92
 	gc := &GraphicContext{
 		draw2dbase.NewStackGraphicContext(),
 		img,
 		painter,
 		raster.NewRasterizer(width, height),
 		raster.NewRasterizer(width, height),
-		&truetype.GlyphBuf{},
-		dpi,
 	}
 	return gc
 }
 
-// GetDPI returns the resolution of the Image GraphicContext
-func (gc *GraphicContext) GetDPI() int {
-	return gc.DPI
-}
-
 // Clear fills the current canvas with a default transparent color
 func (gc *GraphicContext) Clear() {
 	width, height := gc.img.Bounds().Dx(), gc.img.Bounds().Dy()
@@ -140,127 +123,6 @@ func (gc *GraphicContext) StrokeStringAt(text string, x, y float64) (cursor floa
 	return width
 }
 
-func (gc *GraphicContext) loadCurrentFont() (*truetype.Font, error) {
-	font := draw2d.GetFont(gc.Current.FontData)
-	if font == nil {
-		font = draw2d.GetFont(draw2dbase.DefaultFontData)
-	}
-	if font == nil {
-		return nil, errors.New("No font set, and no default font available.")
-	}
-	gc.SetFont(font)
-	gc.SetFontSize(gc.Current.FontSize)
-	return font, nil
-}
-
-// p is a truetype.Point measured in FUnits and positive Y going upwards.
-// The returned value is the same thing measured in floating point and positive Y
-// going downwards.
-
-func (gc *GraphicContext) drawGlyph(glyph truetype.Index, dx, dy float64) error {
-	if err := gc.glyphBuf.Load(gc.Current.Font, fixed.Int26_6(gc.Current.Scale), glyph, font.HintingNone); err != nil {
-		return err
-	}
-	e0 := 0
-	for _, e1 := range gc.glyphBuf.Ends {
-		DrawContour(gc, gc.glyphBuf.Points[e0:e1], dx, dy)
-		e0 = e1
-	}
-	return nil
-}
-
-// CreateStringPath creates a path from the string s at x, y, and returns the string width.
-// The text is placed so that the left edge of the em square of the first character of s
-// and the baseline intersect at x, y. The majority of the affected pixels will be
-// above and to the right of the point, but some may be below or to the left.
-// For example, drawing a string that starts with a 'J' in an italic font may
-// affect pixels below and left of the point.
-func (gc *GraphicContext) CreateStringPath(s string, x, y float64) float64 {
-	f, err := gc.loadCurrentFont()
-	if err != nil {
-		log.Println(err)
-		return 0.0
-	}
-	startx := x
-	prev, hasPrev := truetype.Index(0), false
-	for _, rune := range s {
-		index := f.Index(rune)
-		if hasPrev {
-			x += fUnitsToFloat64(f.Kern(fixed.Int26_6(gc.Current.Scale), prev, index))
-		}
-		err := gc.drawGlyph(index, x, y)
-		if err != nil {
-			log.Println(err)
-			return startx - x
-		}
-		x += fUnitsToFloat64(f.HMetric(fixed.Int26_6(gc.Current.Scale), index).AdvanceWidth)
-		prev, hasPrev = index, true
-	}
-	return x - startx
-}
-
-// GetStringBounds returns the approximate pixel bounds of the string s at x, y.
-// The the left edge of the em square of the first character of s
-// and the baseline intersect at 0, 0 in the returned coordinates.
-// Therefore the top and left coordinates may well be negative.
-func (gc *GraphicContext) GetStringBounds(s string) (left, top, right, bottom float64) {
-	f, err := gc.loadCurrentFont()
-	if err != nil {
-		log.Println(err)
-		return 0, 0, 0, 0
-	}
-	top, left, bottom, right = 10e6, 10e6, -10e6, -10e6
-	cursor := 0.0
-	prev, hasPrev := truetype.Index(0), false
-	for _, rune := range s {
-		index := f.Index(rune)
-		if hasPrev {
-			cursor += fUnitsToFloat64(f.Kern(fixed.Int26_6(gc.Current.Scale), prev, index))
-		}
-		if err := gc.glyphBuf.Load(gc.Current.Font, fixed.Int26_6(gc.Current.Scale), index, font.HintingNone); err != nil {
-			log.Println(err)
-			return 0, 0, 0, 0
-		}
-		e0 := 0
-		for _, e1 := range gc.glyphBuf.Ends {
-			ps := gc.glyphBuf.Points[e0:e1]
-			for _, p := range ps {
-				x, y := pointToF64Point(p)
-				top = math.Min(top, y)
-				bottom = math.Max(bottom, y)
-				left = math.Min(left, x+cursor)
-				right = math.Max(right, x+cursor)
-			}
-		}
-		cursor += fUnitsToFloat64(f.HMetric(fixed.Int26_6(gc.Current.Scale), index).AdvanceWidth)
-		prev, hasPrev = index, true
-	}
-	return left, top, right, bottom
-}
-
-// recalc recalculates scale and bounds values from the font size, screen
-// resolution and font metrics, and invalidates the glyph cache.
-func (gc *GraphicContext) recalc() {
-	gc.Current.Scale = gc.Current.FontSize * float64(gc.DPI) * (64.0 / 72.0)
-}
-
-// SetDPI sets the screen resolution in dots per inch.
-func (gc *GraphicContext) SetDPI(dpi int) {
-	gc.DPI = dpi
-	gc.recalc()
-}
-
-// SetFont sets the font used to draw text.
-func (gc *GraphicContext) SetFont(font *truetype.Font) {
-	gc.Current.Font = font
-}
-
-// SetFontSize sets the font size in points (as in ``a 12 point font'').
-func (gc *GraphicContext) SetFontSize(fontSize float64) {
-	gc.Current.FontSize = fontSize
-	gc.recalc()
-}
-
 func (gc *GraphicContext) paint(rasterizer *raster.Rasterizer, color color.Color) {
 	gc.painter.SetColor(color)
 	rasterizer.Rasterize(gc.painter)

draw2dimg/text.go

@@ -1,82 +0,0 @@
-package draw2dimg
-
-import (
-	"github.com/golang/freetype/truetype"
-	"github.com/llgcode/draw2d"
-
-	"golang.org/x/image/math/fixed"
-)
-
-// DrawContour draws the given closed contour at the given sub-pixel offset.
-func DrawContour(path draw2d.PathBuilder, ps []truetype.Point, dx, dy float64) {
-	if len(ps) == 0 {
-		return
-	}
-	startX, startY := pointToF64Point(ps[0])
-	path.MoveTo(startX+dx, startY+dy)
-	q0X, q0Y, on0 := startX, startY, true
-	for _, p := range ps[1:] {
-		qX, qY := pointToF64Point(p)
-		on := p.Flags&0x01 != 0
-		if on {
-			if on0 {
-				path.LineTo(qX+dx, qY+dy)
-			} else {
-				path.QuadCurveTo(q0X+dx, q0Y+dy, qX+dx, qY+dy)
-			}
-		} else {
-			if on0 {
-				// No-op.
-			} else {
-				midX := (q0X + qX) / 2
-				midY := (q0Y + qY) / 2
-				path.QuadCurveTo(q0X+dx, q0Y+dy, midX+dx, midY+dy)
-			}
-		}
-		q0X, q0Y, on0 = qX, qY, on
-	}
-	// Close the curve.
-	if on0 {
-		path.LineTo(startX+dx, startY+dy)
-	} else {
-		path.QuadCurveTo(q0X+dx, q0Y+dy, startX+dx, startY+dy)
-	}
-}
-
-func pointToF64Point(p truetype.Point) (x, y float64) {
-	return fUnitsToFloat64(p.X), -fUnitsToFloat64(p.Y)
-}
-
-func fUnitsToFloat64(x fixed.Int26_6) float64 {
-	scaled := x << 2
-	return float64(scaled/256) + float64(scaled%256)/256.0
-}
-
-// FontExtents contains font metric information.
-type FontExtents struct {
-	// Ascent is the distance that the text
-	// extends above the baseline.
-	Ascent float64
-
-	// Descent is the distance that the text
-	// extends below the baseline.  The descent
-	// is given as a negative value.
-	Descent float64
-
-	// Height is the distance from the lowest
-	// descending point to the highest ascending
-	// point.
-	Height float64
-}
-
-// Extents returns the FontExtents for a font.
-// TODO needs to read this https://developer.apple.com/fonts/TrueType-Reference-Manual/RM02/Chap2.html#intro
-func Extents(font *truetype.Font, size float64) FontExtents {
-	bounds := font.Bounds(fixed.Int26_6(font.FUnitsPerEm()))
-	scale := size / float64(font.FUnitsPerEm())
-	return FontExtents{
-		Ascent:  float64(bounds.Max.Y) * scale,
-		Descent: float64(bounds.Min.Y) * scale,
-		Height:  float64(bounds.Max.Y-bounds.Min.Y) * scale,
-	}
-}