implemented more methods for pdf graphic context, fixed the code for 100% golint and go vet

pdf2d/fileutil.go

@@ -2,7 +2,7 @@ package pdf2d
 
 import "github.com/stanim/gofpdf"
 
-// SaveToPdfFile create and save a pdf document to a file
+// SaveToPdfFile creates and saves a pdf document to a file
 func SaveToPdfFile(filePath string, pdf *gofpdf.Fpdf) error {
 	return pdf.OutputFileAndClose(filePath)
 }

pdf2d/graphiccontext.go

@@ -1,14 +1,20 @@
 // Copyright 2015 The draw2d Authors. All rights reserved.
 // created: 26/06/2015 by Stani Michiels
+// TODO: fonts, dpi
 
 package pdf2d
 
 import (
+	"bytes"
 	"fmt"
 	"image"
 	"image/color"
+	"image/jpeg"
 	"log"
 	"os"
+	"strconv"
+
+	"code.google.com/p/freetype-go/freetype/truetype"
 
 	"github.com/stanim/draw2d"
 	"github.com/stanim/gofpdf"
@@ -27,11 +33,29 @@ func notImplemented(method string) {
 
 const c255 = 255.0 / 65535.0
 
+var (
+	imageCount uint32
+	white      color.Color = color.RGBA{255, 255, 255, 255}
+)
+
 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)
 }
 
+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 {
@@ -46,69 +70,93 @@ func NewGraphicContext(pdf *gofpdf.Fpdf) *GraphicContext {
 	return &GraphicContext{draw2d.NewStackGraphicContext(), pdf, dpi}
 }
 
+// DrawImage draws an image as JPG at 96dpi
 func (gc *GraphicContext) DrawImage(image image.Image) {
-	notImplemented("DrawImage")
+	name := strconv.Itoa(int(imageCount))
+	tp := "JPG" // "JPG", "JPEG", "PNG" and "GIF"
+	b := &bytes.Buffer{}
+	jpeg.Encode(b, image, nil)
+	gc.pdf.RegisterImageReader(name, tp, b)
+	gc.pdf.Image(name, 0, 0, 0, 0, false, tp, 0, "")
+	// bounds := image.Bounds()
+	// x, y, w, h := float64(bounds.Min.X), float64(bounds.Min.Y), float64(bounds.Dx()), float64(bounds.Dy())
+	//gc.pdf.Image(name, x, y, w, h, false, tp, 0, "")
 }
+
+// Clear draws a white rectangle over the whole page
 func (gc *GraphicContext) Clear() {
-	notImplemented("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) {
-	notImplemented("ClearRect")
+	clearRect(gc, float64(x1), float64(y1), float64(x2), float64(y2))
 }
 
+// SetDPI is a dummy method to implement the GraphicContext interface
 func (gc *GraphicContext) SetDPI(dpi int) {
 	gc.DPI = dpi
+	// gc.recalc()
 }
 
+// GetDPI is a dummy method to implement the GraphicContext interface
 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) {
-	notImplemented("GetStringBounds")
-	return 0, 0, 0, 0
+	_, 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) {
-	notImplemented("CreateStringPath")
-	return 0
+	gc.pdf.MoveTo(x, y)
+	_, _, w, h := gc.GetStringBounds(text)
+	gc.pdf.Cell(w, h, text)
+	return w
 }
 
+// FillString draws a string at 0, 0
 func (gc *GraphicContext) FillString(text string) (cursor float64) {
-	notImplemented("FillString")
-	return 0
+	return gc.FillStringAt(text, 0, 0)
 }
 
+// FillStringAt draws a string at x, y
 func (gc *GraphicContext) FillStringAt(text string, x, y float64) (cursor float64) {
-	notImplemented("FillStringAt")
-	return 0
+	return gc.CreateStringPath(text, x, y)
 }
 
+// StrokeString draws a string at 0, 0
 func (gc *GraphicContext) StrokeString(text string) (cursor float64) {
-	notImplemented("StrokeString")
-	return 0
+	return gc.StrokeStringAt(text, 0, 0)
 }
 
+// StrokeStringAt draws a string at x, y
 func (gc *GraphicContext) StrokeStringAt(text string, x, y float64) (cursor float64) {
-	notImplemented("StrokeStringAt")
-	return 0
+	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.Logger = log.New(os.Stdout, "", log.Lshortfile)
+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(
@@ -123,21 +171,40 @@ func (gc *GraphicContext) draw(style string, paths ...*draw2d.PathStorage) {
 
 // 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 color
 func (gc *GraphicContext) SetFillColor(c color.Color) {
 	gc.StackGraphicContext.SetFillColor(c)
 	gc.pdf.SetFillColor(rgb(c))
 }
 
+// SetFont sets the font used to draw text.
+// It is mandatory to call this method at least once before printing
+// text or the resulting document will not be valid.
+func (gc *GraphicContext) SetFont(font *truetype.Font) {
+	// TODO: this api conflict needs to be fixed
+	gc.pdf.SetFont("Helvetica", "", 12)
+}
+
+// SetFontSize sets the font size in points (as in ``a 12 point font'').
+func (gc *GraphicContext) SetFontSize(fontSize float64) {
+	gc.StackGraphicContext.SetFontSize(fontSize)
+	gc.pdf.SetFontSize(fontSize)
+	//gc.recalc()
+}
+
+// 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])

pdf2d/path_converter.go

@@ -11,14 +11,17 @@ import (
 
 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
@@ -28,6 +31,7 @@ func (c *PathConverter) Convert(paths ...*draw2d.PathStorage) {
 	}
 }
 
+// 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:

pdf2d/path_logger.go

@@ -20,13 +20,15 @@ func ftoas(xs ...float64) string {
 	return buffer.String()
 }
 
-// VertexMatrixTransform implements Vectorizer and applies the Matrix
-// transformation tr. It is normally wrapped around gofpdf Fpdf.
+// PathLogger implements Vectorizer and applies the Matrix
+// transformation tr. It is used as debugging middleware.
+// It should wrap gofpdf.Fpdf directly.
 type PathLogger struct {
 	logger *log.Logger
 	Next   Vectorizer
 }
 
+// NewPathLogger constructs a new PathLogger
 func NewPathLogger(logger *log.Logger,
 	vectorizer Vectorizer) *PathLogger {
 	return &PathLogger{logger, vectorizer}
@@ -51,7 +53,7 @@ func (pl *PathLogger) CurveTo(cx, cy, x, y float64) {
 
 }
 
-// CurveTo adds a cubic bezier curve to the current subpath
+// CurveBezierCubicTo adds a cubic bezier curve to the current subpath
 func (pl *PathLogger) CurveBezierCubicTo(cx1, cy1,
 	cx2, cy2, x, y float64) {
 	pl.logger.Printf("CurveBezierCubicTo(cx1=%.2f, cy1=%.2f, cx2=%.2f, cy2=%.2f, x=%.2f, y=%.2f)", cx1, cy1, cx2, cy2, x, y)

pdf2d/transform.go

@@ -6,12 +6,14 @@ package pdf2d
 import "github.com/stanim/draw2d"
 
 // VertexMatrixTransform implements Vectorizer and applies the Matrix
-// transformation tr. It is normally wrapped around gofpdf Fpdf.
+// transformation tr. It is normally wrapped around gofpdf Fpdf
+// or PathLogger.
 type VertexMatrixTransform struct {
 	tr   draw2d.MatrixTransform
 	Next Vectorizer
 }
 
+// NewVertexMatrixTransform constructs an new VertexMatrixTransform
 func NewVertexMatrixTransform(tr draw2d.MatrixTransform,
 	vectorizer Vectorizer) *VertexMatrixTransform {
 	return &VertexMatrixTransform{tr, vectorizer}
@@ -36,7 +38,7 @@ func (vmt *VertexMatrixTransform) CurveTo(cx, cy, x, y float64) {
 
 }
 
-// CurveTo adds a cubic bezier curve to the current subpath
+// CurveBezierCubicTo adds a cubic bezier curve to the current subpath
 func (vmt *VertexMatrixTransform) CurveBezierCubicTo(cx1, cy1,
 	cx2, cy2, x, y float64) {
 	vmt.tr.Transform(&cx1, &cy1, &cx2, &cy2, &x, &y)

pdf2d/vectorizer.go

@@ -4,6 +4,7 @@
 package pdf2d
 
 // 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