Merge pull request #48 from stanim/pdf

Pdf support

.gitignore

@@ -9,6 +9,8 @@
 **/*.exe
 **/*~
 **/*.orig
+**/*.out
+**/*.test
 core
 _obj
 _test
@@ -17,3 +19,4 @@ _test*
 
 **/*.dll
 **/core*[0-9]
+.private

advanced_path.go

@@ -32,11 +32,13 @@ func RoundRect(path Path, x1, y1, x2, y2, arcWidth, arcHeight float64) {
 }
 
 func Ellipse(path Path, cx, cy, rx, ry float64) {
+	path.MoveTo(cx-rx, cy)
 	path.ArcTo(cx, cy, rx, ry, 0, -math.Pi*2)
 	path.Close()
 }
 
 func Circle(path Path, cx, cy, radius float64) {
+	path.MoveTo(cx-radius, cy)
 	path.ArcTo(cx, cy, radius, radius, 0, -math.Pi*2)
 	path.Close()
 }

draw2dpdf/doc.go

@@ -0,0 +1,5 @@
+// Copyright 2015 The draw2d Authors. All rights reserved.
+// created: 26/06/2015 by Stani Michiels
+
+// Package draw2dpdf provides a Graphic Context that can draw vector form on pdf file.
+package draw2dpdf

draw2dpdf/fileutil.go

@@ -0,0 +1,8 @@
+package draw2dpdf
+
+import "github.com/jung-kurt/gofpdf"
+
+// SaveToPdfFile creates and saves a pdf document to a file
+func SaveToPdfFile(filePath string, pdf *gofpdf.Fpdf) error {
+	return pdf.OutputFileAndClose(filePath)
+}

draw2dpdf/graphiccontext.go

@@ -0,0 +1,326 @@
+// Copyright 2015 The draw2d Authors. All rights reserved.
+// created: 26/06/2015 by Stani Michiels
+// TODO: fonts, dpi
+
+package draw2dpdf
+
+import (
+	"bytes"
+	"image"
+	"image/color"
+	"image/png"
+	"log"
+	"math"
+	"os"
+	"path/filepath"
+	"strconv"
+
+	"code.google.com/p/freetype-go/freetype/truetype"
+
+	"github.com/llgcode/draw2d"
+	"github.com/jung-kurt/gofpdf"
+)
+
+const (
+	c255 = 255.0 / 65535.0
+	// DPI of a pdf document is fixed at 72.
+	DPI = 72
+)
+
+var (
+	caps = map[draw2d.Cap]string{
+		draw2d.RoundCap:  "round",
+		draw2d.ButtCap:   "butt",
+		draw2d.SquareCap: "square"}
+	joins = map[draw2d.Join]string{
+		draw2d.RoundJoin: "round",
+		draw2d.BevelJoin: "bevel",
+		draw2d.MiterJoin: "miter",
+	}
+	imageCount uint32
+	white      color.Color = color.RGBA{255, 255, 255, 255}
+)
+
+// NewPdf creates a new pdf document with the draw2d fontfolder, adds
+// a page and set fill color to white.
+func NewPdf(orientationStr, unitStr, sizeStr string) *gofpdf.Fpdf {
+	pdf := gofpdf.New(orientationStr, unitStr, sizeStr, draw2d.GetFontFolder())
+	pdf.AddPage()
+	pdf.SetFillColor(255, 255, 255) // to be compatible with draw2d
+	return pdf
+}
+
+// rgb converts a color (used by draw2d) into 3 int (used by gofpdf)
+func rgb(c color.Color) (int, int, int) {
+	r, g, b, _ := c.RGBA()
+	return int(float64(r) * c255), int(float64(g) * c255), int(float64(b) * c255)
+}
+
+// clearRect draws a white rectangle
+func clearRect(gc *GraphicContext, x1, y1, x2, y2 float64) {
+	// save state
+	f := gc.Current.FillColor
+	x, y := gc.pdf.GetXY()
+	// cover page with white rectangle
+	gc.SetFillColor(white)
+	draw2d.Rect(gc, x1, y1, x2, y2)
+	gc.Fill()
+	// restore state
+	gc.SetFillColor(f)
+	gc.pdf.MoveTo(x, y)
+}
+
+// GraphicContext implements the draw2d.GraphicContext interface
+// It provides draw2d with a pdf backend (based on gofpdf)
+type GraphicContext struct {
+	*draw2d.StackGraphicContext
+	pdf *gofpdf.Fpdf
+	DPI int
+}
+
+// NewGraphicContext creates a new pdf GraphicContext
+func NewGraphicContext(pdf *gofpdf.Fpdf) *GraphicContext {
+	gc := &GraphicContext{draw2d.NewStackGraphicContext(), pdf, DPI}
+	gc.SetDPI(DPI)
+	return gc
+}
+
+// DrawImage draws an image as PNG
+// TODO: add type (tp) as parameter to argument list?
+func (gc *GraphicContext) DrawImage(image image.Image) {
+	name := strconv.Itoa(int(imageCount))
+	tp := "PNG" // "JPG", "JPEG", "PNG" and "GIF"
+	b := &bytes.Buffer{}
+	png.Encode(b, image)
+	gc.pdf.RegisterImageReader(name, tp, b)
+	bounds := image.Bounds()
+	x0, y0 := float64(bounds.Min.X), float64(bounds.Min.Y)
+	w, h := float64(bounds.Dx()), float64(bounds.Dy())
+	gc.pdf.Image(name, x0, y0, w, h, false, tp, 0, "")
+}
+
+// Clear draws a white rectangle over the whole page
+func (gc *GraphicContext) Clear() {
+	width, height := gc.pdf.GetPageSize()
+	clearRect(gc, 0, 0, width, height)
+}
+
+// ClearRect draws a white rectangle over the specified area
+func (gc *GraphicContext) ClearRect(x1, y1, x2, y2 int) {
+	clearRect(gc, float64(x1), float64(y1), float64(x2), float64(y2))
+}
+
+// recalc recalculates scale and bounds values from the font size, screen
+// resolution and font metrics, and invalidates the glyph cache.
+func (gc *GraphicContext) recalc() {
+	// TODO: resolve properly the font size for pdf and bitmap
+	gc.Current.Scale = 3 * float64(gc.DPI) / 72
+}
+
+// SetDPI sets the DPI which influences the font size.
+func (gc *GraphicContext) SetDPI(dpi int) {
+	gc.DPI = dpi
+	gc.recalc()
+}
+
+// GetDPI returns the DPI which influences the font size.
+// (Note that gofpdf uses a fixed dpi of 72:
+// https://godoc.org/code.google.com/p/gofpdf#Fpdf.PointConvert)
+func (gc *GraphicContext) GetDPI() int {
+	return gc.DPI
+}
+
+// GetStringBounds returns the approximate pixel bounds of the string s at x, y.
+func (gc *GraphicContext) GetStringBounds(s string) (left, top, right, bottom float64) {
+	_, h := gc.pdf.GetFontSize()
+	return 0, 0, gc.pdf.GetStringWidth(s), h
+}
+
+// CreateStringPath creates a path from the string s at x, y, and returns the string width.
+func (gc *GraphicContext) CreateStringPath(text string, x, y float64) (cursor float64) {
+	_, _, w, h := gc.GetStringBounds(text)
+	margin := gc.pdf.GetCellMargin()
+	gc.pdf.MoveTo(x-margin, y+margin-0.82*h)
+	gc.pdf.CellFormat(w, h, text, "", 0, "BL", false, 0, "")
+	//	gc.pdf.Cell(w, h, text)
+	return w
+}
+
+// FillString draws a string at 0, 0
+func (gc *GraphicContext) FillString(text string) (cursor float64) {
+	return gc.FillStringAt(text, 0, 0)
+}
+
+// FillStringAt draws a string at x, y
+func (gc *GraphicContext) FillStringAt(text string, x, y float64) (cursor float64) {
+	return gc.CreateStringPath(text, x, y)
+}
+
+// StrokeString draws a string at 0, 0 (stroking is unsupported,
+// string will be filled)
+func (gc *GraphicContext) StrokeString(text string) (cursor float64) {
+	return gc.StrokeStringAt(text, 0, 0)
+}
+
+// StrokeStringAt draws a string at x, y (stroking is unsupported,
+// string will be filled)
+func (gc *GraphicContext) StrokeStringAt(text string, x, y float64) (cursor float64) {
+	return gc.CreateStringPath(text, x, y)
+}
+
+// Stroke strokes the paths
+func (gc *GraphicContext) Stroke(paths ...*draw2d.PathStorage) {
+	gc.draw("D", paths...)
+}
+
+// Fill strokes the paths
+func (gc *GraphicContext) Fill(paths ...*draw2d.PathStorage) {
+	gc.draw("F", paths...)
+}
+
+// FillStroke first fills the paths and than strokes them
+func (gc *GraphicContext) FillStroke(paths ...*draw2d.PathStorage) {
+	gc.draw("FD", paths...)
+}
+
+var logger = log.New(os.Stdout, "", log.Lshortfile)
+
+// draw fills and/or strokes paths
+func (gc *GraphicContext) draw(style string, paths ...*draw2d.PathStorage) {
+	paths = append(paths, gc.Current.Path)
+	pathConverter := NewPathConverter(gc.pdf)
+	// pathConverter := NewPathConverter(NewPathLogger(logger, gc.pdf))
+	pathConverter.Convert(paths...)
+	if gc.Current.FillRule.UseNonZeroWinding() {
+		style += "*"
+	}
+	gc.pdf.DrawPath(style)
+}
+
+// overwrite StackGraphicContext methods
+
+// SetStrokeColor sets the stroke color
+func (gc *GraphicContext) SetStrokeColor(c color.Color) {
+	gc.StackGraphicContext.SetStrokeColor(c)
+	gc.pdf.SetDrawColor(rgb(c))
+}
+
+// SetFillColor sets the fill and text color
+func (gc *GraphicContext) SetFillColor(c color.Color) {
+	gc.StackGraphicContext.SetFillColor(c)
+	gc.pdf.SetFillColor(rgb(c))
+	gc.pdf.SetTextColor(rgb(c))
+}
+
+// SetFont is unsupported by the pdf graphic context, use SetFontData
+// instead.
+func (gc *GraphicContext) SetFont(font *truetype.Font) {
+	// TODO: what to do with this api conflict between draw2d and gofpdf?!
+}
+
+// SetFontData sets the current font used to draw text. Always use
+// this method, as SetFont is unsupported by the pdf graphic context.
+// It is mandatory to call this method at least once before printing
+// text or the resulting document will not be valid.
+// It is necessary to generate a font definition file first with the
+// makefont utility. It is not necessary to call this function for the
+// core PDF fonts (courier, helvetica, times, zapfdingbats).
+// go get github.com/jung-kurt/gofpdf/makefont
+// http://godoc.org/github.com/jung-kurt/gofpdf#Fpdf.AddFont
+func (gc *GraphicContext) SetFontData(fontData draw2d.FontData) {
+	// TODO: call Makefont embed if json file does not exist yet
+	gc.StackGraphicContext.SetFontData(fontData)
+	var style string
+	if fontData.Style&draw2d.FontStyleBold != 0 {
+		style += "B"
+	}
+	if fontData.Style&draw2d.FontStyleItalic != 0 {
+		style += "I"
+	}
+	fn := draw2d.FontFileName(fontData)
+	fn = fn[:len(fn)-4]
+	jfn := filepath.Join(draw2d.GetFontFolder(), fn+".json")
+	gc.pdf.AddFont(fn, style, jfn)
+}
+
+// SetFontSize sets the font size in points (as in ``a 12 point font'').
+// TODO: resolve this with ImgGraphicContext (now done with gc.Current.Scale)
+func (gc *GraphicContext) SetFontSize(fontSize float64) {
+	gc.StackGraphicContext.SetFontSize(fontSize)
+	gc.recalc()
+	gc.pdf.SetFontSize(fontSize * gc.Current.Scale)
+}
+
+// SetLineWidth sets the line width
+func (gc *GraphicContext) SetLineWidth(LineWidth float64) {
+	gc.StackGraphicContext.SetLineWidth(LineWidth)
+	gc.pdf.SetLineWidth(LineWidth)
+}
+
+// SetLineCap sets the line cap (round, but or square)
+func (gc *GraphicContext) SetLineCap(Cap draw2d.Cap) {
+	gc.StackGraphicContext.SetLineCap(Cap)
+	gc.pdf.SetLineCapStyle(caps[Cap])
+}
+
+// SetLineJoin sets the line cap (round, bevel or miter)
+func (gc *GraphicContext) SetLineJoin(Join draw2d.Join) {
+	gc.StackGraphicContext.SetLineJoin(Join)
+	gc.pdf.SetLineJoinStyle(joins[Join])
+}
+
+// Transformations
+
+// Scale generally scales the following text, drawings and images.
+// sx and sy are the scaling factors for width and height.
+// This must be placed between gc.Save() and gc.Restore(), otherwise
+// the pdf is invalid.
+func (gc *GraphicContext) Scale(sx, sy float64) {
+	gc.StackGraphicContext.Scale(sx, sy)
+	gc.pdf.TransformScale(sx*100, sy*100, 0, 0)
+}
+
+// Rotate rotates the following text, drawings and images.
+// Angle is specified in radians and measured clockwise from the
+// 3 o'clock position.
+// This must be placed between gc.Save() and gc.Restore(), otherwise
+// the pdf is invalid.
+func (gc *GraphicContext) Rotate(angle float64) {
+	gc.StackGraphicContext.Rotate(angle)
+	gc.pdf.TransformRotate(-angle*180/math.Pi, 0, 0)
+}
+
+// Translate moves the following text, drawings and images
+// horizontally and vertically by the amounts specified by tx and ty.
+// This must be placed between gc.Save() and gc.Restore(), otherwise
+// the pdf is invalid.
+func (gc *GraphicContext) Translate(tx, ty float64) {
+	gc.StackGraphicContext.Translate(tx, ty)
+	gc.pdf.TransformTranslate(tx, ty)
+}
+
+// Save saves the current context stack
+// (transformation, font, color,...).
+func (gc *GraphicContext) Save() {
+	gc.StackGraphicContext.Save()
+	gc.pdf.TransformBegin()
+}
+
+// Restore restores the current context stack
+// (transformation, color,...). Restoring the font is not supported.
+func (gc *GraphicContext) Restore() {
+	gc.pdf.TransformEnd()
+	gc.StackGraphicContext.Restore()
+	c := gc.Current
+	gc.SetFontSize(c.FontSize)
+	// gc.SetFontData(c.FontData) unsupported, causes bug (do not enable)
+	gc.SetLineWidth(c.LineWidth)
+	gc.SetStrokeColor(c.StrokeColor)
+	gc.SetFillColor(c.FillColor)
+	gc.SetFillRule(c.FillRule)
+	// gc.SetLineDash(c.Dash, c.DashOffset) // TODO
+	gc.SetLineCap(c.Cap)
+	gc.SetLineJoin(c.Join)
+	// c.Path unsupported
+	// c.Font unsupported
+}

draw2dpdf/graphiccontext_test.go

@@ -0,0 +1,35 @@
+package draw2dpdf
+
+import (
+	"fmt"
+	"image/color"
+
+	"github.com/llgcode/draw2d"
+	"github.com/jung-kurt/gofpdf"
+)
+
+func ExampleGraphicContext() {
+	// Initialize the graphic context on a pdf document
+	pdf := gofpdf.New("P", "mm", "A4", "../font")
+	pdf.AddPage()
+	gc := NewGraphicContext(pdf)
+
+	// some properties
+	gc.SetFillColor(color.RGBA{0x44, 0xff, 0x44, 0xff})
+	gc.SetStrokeColor(color.RGBA{0x44, 0x44, 0x44, 0xff})
+	gc.SetLineCap(draw2d.RoundCap)
+	gc.SetLineWidth(5)
+
+	// draw something
+	gc.MoveTo(10, 10) // should always be called first for a new path
+	gc.LineTo(100, 50)
+	gc.QuadCurveTo(100, 10, 10, 10)
+	gc.Close()
+	gc.FillStroke()
+	fmt.Println(gc.LastPoint())
+
+	// draw2dpdf.SaveToPdfFile("example.pdf", pdf)
+
+	// Output:
+	// 10 10
+}

draw2dpdf/path_converter.go

@@ -0,0 +1,60 @@
+// Copyright 2015 The draw2d Authors. All rights reserved.
+// created: 26/06/2015 by Stani Michiels
+
+package draw2dpdf
+
+import (
+	"math"
+
+	"github.com/llgcode/draw2d"
+)
+
+const deg = 180 / math.Pi
+
+// PathConverter converts the paths to the pdf api
+type PathConverter struct {
+	pdf Vectorizer
+}
+
+// NewPathConverter constructs a PathConverter from a pdf vectorizer
+func NewPathConverter(pdf Vectorizer) *PathConverter {
+	return &PathConverter{pdf: pdf}
+}
+
+// Convert converts the paths to the pdf api
+func (c *PathConverter) Convert(paths ...*draw2d.PathStorage) {
+	for _, path := range paths {
+		j := 0
+		for _, cmd := range path.Commands {
+			j = j + c.ConvertCommand(cmd, path.Vertices[j:]...)
+		}
+	}
+}
+
+// ConvertCommand converts a single path segment to the pdf api
+func (c *PathConverter) ConvertCommand(cmd draw2d.PathCmd, vertices ...float64) int {
+	switch cmd {
+	case draw2d.MoveTo:
+		c.pdf.MoveTo(vertices[0], vertices[1])
+		return 2
+	case draw2d.LineTo:
+		c.pdf.LineTo(vertices[0], vertices[1])
+		return 2
+	case draw2d.QuadCurveTo:
+		c.pdf.CurveTo(vertices[0], vertices[1], vertices[2], vertices[3])
+		return 4
+	case draw2d.CubicCurveTo:
+		c.pdf.CurveBezierCubicTo(vertices[0], vertices[1], vertices[2], vertices[3], vertices[4], vertices[5])
+		return 6
+	case draw2d.ArcTo:
+		c.pdf.ArcTo(vertices[0], vertices[1], vertices[2], vertices[3],
+			0,                             // degRotate
+			vertices[4]*deg,               // degStart = startAngle
+			(vertices[4]-vertices[5])*deg) // degEnd = startAngle-angle
+		return 6
+	case draw2d.Close:
+		c.pdf.ClosePath()
+		return 0
+	}
+	return 0
+}

draw2dpdf/samples_test.go

@@ -0,0 +1,49 @@
+// See also test_test.go
+
+package draw2dpdf_test
+
+import (
+	"testing"
+
+	"github.com/llgcode/draw2d"
+	"github.com/llgcode/draw2d.samples"
+	"github.com/llgcode/draw2d.samples/android"
+	"github.com/llgcode/draw2d.samples/frameimage"
+	"github.com/llgcode/draw2d.samples/gopher"
+	"github.com/llgcode/draw2d.samples/helloworld"
+	"github.com/llgcode/draw2d.samples/line"
+	"github.com/llgcode/draw2d.samples/linecapjoin"
+	"github.com/llgcode/draw2d.samples/postscript"
+)
+
+func TestSampleAndroid(t *testing.T) {
+	test(t, android.Main)
+}
+
+func TestSampleGopher(t *testing.T) {
+	test(t, gopher.Main)
+}
+
+func TestSampleHelloWorld(t *testing.T) {
+	// Set the global folder for searching fonts
+	// The pdf backend needs for every ttf file its corresponding json
+	// file which is generated by gofpdf/makefont.
+	draw2d.SetFontFolder(samples.Dir("helloworld", "../"))
+	test(t, helloworld.Main)
+}
+
+func TestSampleFrameImage(t *testing.T) {
+	test(t, frameimage.Main)
+}
+
+func TestSampleLine(t *testing.T) {
+	test(t, line.Main)
+}
+
+func TestSampleLineCap(t *testing.T) {
+	test(t, linecapjoin.Main)
+}
+
+func TestSamplePostscript(t *testing.T) {
+	test(t, postscript.Main)
+}

draw2dpdf/test_test.go

@@ -0,0 +1,33 @@
+// Package draw2dpdf_test gives test coverage with the command:
+// go test -cover ./... | grep -v "no test"
+// (It should be run from its parent draw2d directory.)
+package draw2dpdf_test
+
+import (
+	"os"
+	"testing"
+
+	"github.com/llgcode/draw2d"
+	"github.com/llgcode/draw2d/draw2dpdf"
+)
+
+func test(t *testing.T, sample draw2d.Sample) {
+	// Initialize the graphic context on an pdf document
+	dest := draw2dpdf.NewPdf("L", "mm", "A4")
+	gc := draw2dpdf.NewGraphicContext(dest)
+	// Draw sample
+	fn, err := sample(gc, "pdf")
+	if err != nil {
+		t.Errorf("Drawing %q failed: %v", fn, err)
+		return
+	}
+	// Save to pdf only if it doesn't exist because of git
+	if _, err = os.Stat(fn); err == nil {
+		t.Skipf("Saving %q skipped, as it exists already. (Git would consider it modified.)", fn)
+		return
+	}
+	err = draw2dpdf.SaveToPdfFile(fn, dest)
+	if err != nil {
+		t.Errorf("Saving %q failed: %v", fn, err)
+	}
+}

draw2dpdf/vectorizer.go

@@ -0,0 +1,22 @@
+// Copyright 2015 The draw2d Authors. All rights reserved.
+// created: 26/06/2015 by Stani Michiels
+
+package draw2dpdf
+
+// Vectorizer defines the minimal interface for gofpdf.Fpdf
+// to be passed to a PathConvertor.
+// It is also implemented by for example VertexMatrixTransform
+type Vectorizer interface {
+	// MoveTo creates a new subpath that start at the specified point
+	MoveTo(x, y float64)
+	// LineTo adds a line to the current subpath
+	LineTo(x, y float64)
+	// CurveTo adds a quadratic bezier curve to the current subpath
+	CurveTo(cx, cy, x, y float64)
+	// CurveTo adds a cubic bezier curve to the current subpath
+	CurveBezierCubicTo(cx1, cy1, cx2, cy2, x, y float64)
+	// ArcTo adds an arc to the current subpath
+	ArcTo(x, y, rx, ry, degRotate, degStart, degEnd float64)
+	// ClosePath closes the subpath
+	ClosePath()
+}

font.go

@@ -38,7 +38,7 @@ type FontData struct {
 	Style  FontStyle
 }
 
-func fontFileName(fontData FontData) string {
+func FontFileName(fontData FontData) string {
 	fontFileName := fontData.Name
 	switch fontData.Family {
 	case FontFamilySans:
@@ -62,11 +62,11 @@ func fontFileName(fontData FontData) string {
 }
 
 func RegisterFont(fontData FontData, font *truetype.Font) {
-	fonts[fontFileName(fontData)] = font
+	fonts[FontFileName(fontData)] = font
 }
 
 func GetFont(fontData FontData) *truetype.Font {
-	fontFileName := fontFileName(fontData)
+	fontFileName := FontFileName(fontData)
 	font := fonts[fontFileName]
 	if font != nil {
 		return font

gc.go

@@ -15,6 +15,8 @@ const (
 	FillRuleWinding
 )
 
+type Sample func(gc GraphicContext, ext string) (string, error)
+
 type GraphicContext interface {
 	Path
 	// Create a new path

image.go

@@ -164,7 +164,7 @@ func (gc *ImageGraphicContext) drawContour(ps []truetype.Point, dx, dy float64)
 }
 
 func (gc *ImageGraphicContext) drawGlyph(glyph truetype.Index, dx, dy float64) error {
-	if err := gc.glyphBuf.Load(gc.Current.font, gc.Current.scale, glyph, truetype.NoHinting); err != nil {
+	if err := gc.glyphBuf.Load(gc.Current.Font, int32(gc.Current.Scale), glyph, truetype.NoHinting); err != nil {
 		return err
 	}
 	e0 := 0
@@ -192,14 +192,14 @@ func (gc *ImageGraphicContext) CreateStringPath(s string, x, y float64) float64
 	for _, rune := range s {
 		index := font.Index(rune)
 		if hasPrev {
-			x += fUnitsToFloat64(font.Kerning(gc.Current.scale, prev, index))
+			x += fUnitsToFloat64(font.Kerning(int32(gc.Current.Scale), prev, index))
 		}
 		err := gc.drawGlyph(index, x, y)
 		if err != nil {
 			log.Println(err)
 			return startx - x
 		}
-		x += fUnitsToFloat64(font.HMetric(gc.Current.scale, index).AdvanceWidth)
+		x += fUnitsToFloat64(font.HMetric(int32(gc.Current.Scale), index).AdvanceWidth)
 		prev, hasPrev = index, true
 	}
 	return x - startx
@@ -221,9 +221,9 @@ func (gc *ImageGraphicContext) GetStringBounds(s string) (left, top, right, bott
 	for _, rune := range s {
 		index := font.Index(rune)
 		if hasPrev {
-			cursor += fUnitsToFloat64(font.Kerning(gc.Current.scale, prev, index))
+			cursor += fUnitsToFloat64(font.Kerning(int32(gc.Current.Scale), prev, index))
 		}
-		if err := gc.glyphBuf.Load(gc.Current.font, gc.Current.scale, index, truetype.NoHinting); err != nil {
+		if err := gc.glyphBuf.Load(gc.Current.Font, int32(gc.Current.Scale), index, truetype.NoHinting); err != nil {
 			log.Println(err)
 			return 0, 0, 0, 0
 		}
@@ -238,7 +238,7 @@ func (gc *ImageGraphicContext) GetStringBounds(s string) (left, top, right, bott
 				right = math.Max(right, x+cursor)
 			}
 		}
-		cursor += fUnitsToFloat64(font.HMetric(gc.Current.scale, index).AdvanceWidth)
+		cursor += fUnitsToFloat64(font.HMetric(int32(gc.Current.Scale), index).AdvanceWidth)
 		prev, hasPrev = index, true
 	}
 	return left, top, right, bottom
@@ -247,7 +247,7 @@ func (gc *ImageGraphicContext) GetStringBounds(s string) (left, top, right, bott
 // recalc recalculates scale and bounds values from the font size, screen
 // resolution and font metrics, and invalidates the glyph cache.
 func (gc *ImageGraphicContext) recalc() {
-	gc.Current.scale = int32(gc.Current.FontSize * float64(gc.DPI) * (64.0 / 72.0))
+	gc.Current.Scale = gc.Current.FontSize * float64(gc.DPI) * (64.0 / 72.0)
 }
 
 // SetDPI sets the screen resolution in dots per inch.
@@ -258,7 +258,7 @@ func (gc *ImageGraphicContext) SetDPI(dpi int) {
 
 // SetFont sets the font used to draw text.
 func (gc *ImageGraphicContext) SetFont(font *truetype.Font) {
-	gc.Current.font = font
+	gc.Current.Font = font
 }
 
 // SetFontSize sets the font size in points (as in ``a 12 point font'').

path_adder.go

@@ -43,23 +43,23 @@ func NewPathAdder(adder raster.Adder) *PathAdder {
 func (pathAdder *PathAdder) Convert(paths ...*PathStorage) {
 	for _, path := range paths {
 		j := 0
-		for _, cmd := range path.commands {
+		for _, cmd := range path.Commands {
 			switch cmd {
 			case MoveTo:
-				pathAdder.firstPoint = raster.Point{raster.Fix32(path.vertices[j] * 256), raster.Fix32(path.vertices[j+1] * 256)}
+				pathAdder.firstPoint = raster.Point{raster.Fix32(path.Vertices[j] * 256), raster.Fix32(path.Vertices[j+1] * 256)}
 				pathAdder.adder.Start(pathAdder.firstPoint)
 				j += 2
 			case LineTo:
-				pathAdder.adder.Add1(raster.Point{raster.Fix32(path.vertices[j] * 256), raster.Fix32(path.vertices[j+1] * 256)})
+				pathAdder.adder.Add1(raster.Point{raster.Fix32(path.Vertices[j] * 256), raster.Fix32(path.Vertices[j+1] * 256)})
 				j += 2
 			case QuadCurveTo:
-				pathAdder.adder.Add2(raster.Point{raster.Fix32(path.vertices[j] * 256), raster.Fix32(path.vertices[j+1] * 256)}, raster.Point{raster.Fix32(path.vertices[j+2] * 256), raster.Fix32(path.vertices[j+3] * 256)})
+				pathAdder.adder.Add2(raster.Point{raster.Fix32(path.Vertices[j] * 256), raster.Fix32(path.Vertices[j+1] * 256)}, raster.Point{raster.Fix32(path.Vertices[j+2] * 256), raster.Fix32(path.Vertices[j+3] * 256)})
 				j += 4
 			case CubicCurveTo:
-				pathAdder.adder.Add3(raster.Point{raster.Fix32(path.vertices[j] * 256), raster.Fix32(path.vertices[j+1] * 256)}, raster.Point{raster.Fix32(path.vertices[j+2] * 256), raster.Fix32(path.vertices[j+3] * 256)}, raster.Point{raster.Fix32(path.vertices[j+4] * 256), raster.Fix32(path.vertices[j+5] * 256)})
+				pathAdder.adder.Add3(raster.Point{raster.Fix32(path.Vertices[j] * 256), raster.Fix32(path.Vertices[j+1] * 256)}, raster.Point{raster.Fix32(path.Vertices[j+2] * 256), raster.Fix32(path.Vertices[j+3] * 256)}, raster.Point{raster.Fix32(path.Vertices[j+4] * 256), raster.Fix32(path.Vertices[j+5] * 256)})
 				j += 6
 			case ArcTo:
-				lastPoint := arcAdder(pathAdder.adder, path.vertices[j], path.vertices[j+1], path.vertices[j+2], path.vertices[j+3], path.vertices[j+4], path.vertices[j+5], pathAdder.ApproximationScale)
+				lastPoint := arcAdder(pathAdder.adder, path.Vertices[j], path.Vertices[j+1], path.Vertices[j+2], path.Vertices[j+3], path.Vertices[j+4], path.Vertices[j+5], pathAdder.ApproximationScale)
 				pathAdder.adder.Add1(lastPoint)
 				j += 6
 			case Close:

path_converter.go

@@ -20,8 +20,8 @@ func NewPathConverter(converter VertexConverter) *PathConverter {
 func (c *PathConverter) Convert(paths ...*PathStorage) {
 	for _, path := range paths {
 		j := 0
-		for _, cmd := range path.commands {
-			j = j + c.ConvertCommand(cmd, path.vertices[j:]...)
+		for _, cmd := range path.Commands {
+			j = j + c.ConvertCommand(cmd, path.Vertices[j:]...)
 		}
 		c.converter.NextCommand(VertexStopCommand)
 	}

path_storage.go

@@ -20,45 +20,45 @@ const (
 )
 
 type PathStorage struct {
-	commands []PathCmd
-	vertices []float64
+	Commands []PathCmd
+	Vertices []float64
 	x, y     float64
 }
 
 func NewPathStorage() (p *PathStorage) {
 	p = new(PathStorage)
-	p.commands = make([]PathCmd, 0, 256)
-	p.vertices = make([]float64, 0, 256)
+	p.Commands = make([]PathCmd, 0, 256)
+	p.Vertices = make([]float64, 0, 256)
 	return
 }
 
 func (p *PathStorage) Clear() {
-	p.commands = p.commands[0:0]
-	p.vertices = p.vertices[0:0]
+	p.Commands = p.Commands[0:0]
+	p.Vertices = p.Vertices[0:0]
 	return
 }
 
-func (p *PathStorage) appendToPath(cmd PathCmd, vertices ...float64) {
-	if cap(p.vertices) <= len(p.vertices)+6 {
-		a := make([]PathCmd, len(p.commands), cap(p.commands)+256)
-		b := make([]float64, len(p.vertices), cap(p.vertices)+256)
-		copy(a, p.commands)
-		p.commands = a
-		copy(b, p.vertices)
-		p.vertices = b
+func (p *PathStorage) appendToPath(cmd PathCmd, Vertices ...float64) {
+	if cap(p.Vertices) <= len(p.Vertices)+6 {
+		a := make([]PathCmd, len(p.Commands), cap(p.Commands)+256)
+		b := make([]float64, len(p.Vertices), cap(p.Vertices)+256)
+		copy(a, p.Commands)
+		p.Commands = a
+		copy(b, p.Vertices)
+		p.Vertices = b
 	}
-	p.commands = p.commands[0 : len(p.commands)+1]
-	p.commands[len(p.commands)-1] = cmd
-	copy(p.vertices[len(p.vertices):len(p.vertices)+len(vertices)], vertices)
-	p.vertices = p.vertices[0 : len(p.vertices)+len(vertices)]
+	p.Commands = p.Commands[0 : len(p.Commands)+1]
+	p.Commands[len(p.Commands)-1] = cmd
+	copy(p.Vertices[len(p.Vertices):len(p.Vertices)+len(Vertices)], Vertices)
+	p.Vertices = p.Vertices[0 : len(p.Vertices)+len(Vertices)]
 }
 
 func (src *PathStorage) Copy() (dest *PathStorage) {
 	dest = new(PathStorage)
-	dest.commands = make([]PathCmd, len(src.commands))
-	copy(dest.commands, src.commands)
-	dest.vertices = make([]float64, len(src.vertices))
-	copy(dest.vertices, src.vertices)
+	dest.Commands = make([]PathCmd, len(src.Commands))
+	copy(dest.Commands, src.Commands)
+	dest.Vertices = make([]float64, len(src.Vertices))
+	copy(dest.Vertices, src.Vertices)
 	return dest
 }
 
@@ -67,7 +67,7 @@ func (p *PathStorage) LastPoint() (x, y float64) {
 }
 
 func (p *PathStorage) IsEmpty() bool {
-	return len(p.commands) == 0
+	return len(p.Commands) == 0
 }
 
 func (p *PathStorage) Close() *PathStorage {
@@ -145,7 +145,7 @@ func (p *PathStorage) ArcTo(cx, cy, rx, ry, startAngle, angle float64) *PathStor
 	}
 	startX := cx + math.Cos(startAngle)*rx
 	startY := cy + math.Sin(startAngle)*ry
-	if len(p.commands) > 0 {
+	if len(p.Commands) > 0 {
 		p.LineTo(startX, startY)
 	} else {
 		p.MoveTo(startX, startY)
@@ -165,22 +165,22 @@ func (p *PathStorage) RArcTo(dcx, dcy, rx, ry, startAngle, angle float64) *PathS
 func (p *PathStorage) String() string {
 	s := ""
 	j := 0
-	for _, cmd := range p.commands {
+	for _, cmd := range p.Commands {
 		switch cmd {
 		case MoveTo:
-			s += fmt.Sprintf("MoveTo: %f, %f\n", p.vertices[j], p.vertices[j+1])
+			s += fmt.Sprintf("MoveTo: %f, %f\n", p.Vertices[j], p.Vertices[j+1])
 			j = j + 2
 		case LineTo:
-			s += fmt.Sprintf("LineTo: %f, %f\n", p.vertices[j], p.vertices[j+1])
+			s += fmt.Sprintf("LineTo: %f, %f\n", p.Vertices[j], p.Vertices[j+1])
 			j = j + 2
 		case QuadCurveTo:
-			s += fmt.Sprintf("QuadCurveTo: %f, %f, %f, %f\n", p.vertices[j], p.vertices[j+1], p.vertices[j+2], p.vertices[j+3])
+			s += fmt.Sprintf("QuadCurveTo: %f, %f, %f, %f\n", p.Vertices[j], p.Vertices[j+1], p.Vertices[j+2], p.Vertices[j+3])
 			j = j + 4
 		case CubicCurveTo:
-			s += fmt.Sprintf("CubicCurveTo: %f, %f, %f, %f, %f, %f\n", p.vertices[j], p.vertices[j+1], p.vertices[j+2], p.vertices[j+3], p.vertices[j+4], p.vertices[j+5])
+			s += fmt.Sprintf("CubicCurveTo: %f, %f, %f, %f, %f, %f\n", p.Vertices[j], p.Vertices[j+1], p.Vertices[j+2], p.Vertices[j+3], p.Vertices[j+4], p.Vertices[j+5])
 			j = j + 6
 		case ArcTo:
-			s += fmt.Sprintf("ArcTo: %f, %f, %f, %f, %f, %f\n", p.vertices[j], p.vertices[j+1], p.vertices[j+2], p.vertices[j+3], p.vertices[j+4], p.vertices[j+5])
+			s += fmt.Sprintf("ArcTo: %f, %f, %f, %f, %f, %f\n", p.Vertices[j], p.Vertices[j+1], p.Vertices[j+2], p.Vertices[j+3], p.Vertices[j+4], p.Vertices[j+5])
 			j = j + 6
 		case Close:
 			s += "Close\n"

samples_test.go

@@ -0,0 +1,47 @@
+// See also test_test.go
+
+package draw2d_test
+
+import (
+	"testing"
+
+	"github.com/llgcode/draw2d"
+	"github.com/llgcode/draw2d.samples"
+	"github.com/llgcode/draw2d.samples/android"
+	"github.com/llgcode/draw2d.samples/frameimage"
+	"github.com/llgcode/draw2d.samples/gopher"
+	"github.com/llgcode/draw2d.samples/helloworld"
+	"github.com/llgcode/draw2d.samples/line"
+	"github.com/llgcode/draw2d.samples/linecapjoin"
+	"github.com/llgcode/draw2d.samples/postscript"
+)
+
+func TestSampleAndroid(t *testing.T) {
+	test(t, android.Main)
+}
+
+func TestSampleGopher(t *testing.T) {
+	test(t, gopher.Main)
+}
+
+func TestSampleHelloWorld(t *testing.T) {
+	// Set the global folder for searching fonts
+	draw2d.SetFontFolder(samples.Dir("helloworld", ""))
+	test(t, helloworld.Main)
+}
+
+func TestSampleFrameImage(t *testing.T) {
+	test(t, frameimage.Main)
+}
+
+func TestSampleLine(t *testing.T) {
+	test(t, line.Main)
+}
+
+func TestSampleLineCap(t *testing.T) {
+	test(t, linecapjoin.Main)
+}
+
+func TestSamplePostscript(t *testing.T) {
+	test(t, postscript.Main)
+}

stack_gc.go

@@ -28,10 +28,10 @@ type ContextStack struct {
 	FontSize    float64
 	FontData    FontData
 
-	font *truetype.Font
+	Font *truetype.Font
 	// fontSize and dpi are used to calculate scale. scale is the number of
 	// 26.6 fixed point units in 1 em.
-	scale int32
+	Scale float64
 
 	previous *ContextStack
 }
@@ -193,8 +193,8 @@ func (gc *StackGraphicContext) Save() {
 	context.Cap = gc.Current.Cap
 	context.Join = gc.Current.Join
 	context.Path = gc.Current.Path.Copy()
-	context.font = gc.Current.font
-	context.scale = gc.Current.scale
+	context.Font = gc.Current.Font
+	context.Scale = gc.Current.Scale
 	copy(context.Tr[:], gc.Current.Tr[:])
 	context.previous = gc.Current
 	gc.Current = context

test_test.go

@@ -0,0 +1,27 @@
+// Package draw2d_test gives test coverage with the command:
+// go test -cover ./... | grep -v "no test"
+package draw2d_test
+
+import (
+	"image"
+	"testing"
+
+	"github.com/llgcode/draw2d"
+)
+
+func test(t *testing.T, draw draw2d.Sample) {
+	// Initialize the graphic context on an RGBA image
+	dest := image.NewRGBA(image.Rect(0, 0, 297, 210.0))
+	gc := draw2d.NewGraphicContext(dest)
+	// Draw Android logo
+	fn, err := draw(gc, "png")
+	if err != nil {
+		t.Errorf("Drawing %q failed: %v", fn, err)
+		return
+	}
+	// Save to png
+	err = draw2d.SaveToPngFile(fn, dest)
+	if err != nil {
+		t.Errorf("Saving %q failed: %v", fn, err)
+	}
+}