unidoc · gunnsth · Mar 2, 2020 · Oct 15, 2019 · Oct 16, 2019 · Oct 16, 2019
diff --git a/go.mod b/go.mod
@@ -1,14 +1,12 @@
 module github.com/unidoc/unipdf/v3
 
 require (
+	github.com/adrg/sysfont v0.1.0
 	github.com/boombuler/barcode v1.0.0
+	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0
 	github.com/gunnsth/pkcs7 v0.0.0-20181213175627-3cffc6fbfe83
 	github.com/stretchr/testify v1.3.0
 	golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5
 	golang.org/x/image v0.0.0-20181116024801-cd38e8056d9b
-	golang.org/x/lint v0.0.0-20190409202823-959b441ac422 // indirect
-	golang.org/x/net v0.0.0-20190606173856-1492cefac77f // indirect
-	golang.org/x/sys v0.0.0-20190606203320-7fc4e5ec1444 // indirect
 	golang.org/x/text v0.3.2
-	golang.org/x/tools v0.0.0-20190606174628-0139d5756a7d // indirect
 )
diff --git a/go.sum b/go.sum
@@ -1,7 +1,14 @@
+github.com/adrg/strutil v0.1.0 h1:IOQnSOAjbE17+7l1lw4rXgX6JuSeJGdZa7BucTMV3Qg=
+github.com/adrg/strutil v0.1.0/go.mod h1:pXRr2+IyX5AEPAF5icj/EeTaiflPSD2hvGjnguilZgE=
+github.com/adrg/sysfont v0.1.0 h1:vOk13USVkciGOJj9sPT9Gl9zfHUT2HZgsBnwS1Je4Q8=
+github.com/adrg/sysfont v0.1.0/go.mod h1:DzISco90USPZJ+lmtpuz1SOTn1fih6YyB0KG2TEP/0U=
+github.com/adrg/xdg v0.2.1 h1:VSVdnH7cQ7V+B33qSJHTCRlNgra1607Q8PzEmnvb2Ic=
+github.com/adrg/xdg v0.2.1/go.mod h1:ZuOshBmzV4Ta+s23hdfFZnBsdzmoR3US0d7ErpqSbTQ=
 github.com/boombuler/barcode v1.0.0 h1:s1TvRnXwL2xJRaccrdcBQMZxq6X7DvsMogtmJeHDdrc=
 github.com/boombuler/barcode v1.0.0/go.mod h1:paBWMcWSl3LHKBqUq+rly7CNSldXjb2rDl3JlRe0mD8=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
 github.com/gunnsth/pkcs7 v0.0.0-20181213175627-3cffc6fbfe83 h1:saj5dTV7eQ1wFg/gVZr1SfbkOmg8CYO9R8frHgQiyR4=
 github.com/gunnsth/pkcs7 v0.0.0-20181213175627-3cffc6fbfe83/go.mod h1:xaGEIRenAiJcGgd9p62zbiP4993KaV3PdjczwGnP50I=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -10,26 +17,15 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c h1:Vj5n4GlwjmQteupaxJ9+0FNOmBrHfq7vN4btdGoDZgI=
-golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5 h1:58fnuSXlxZmFdJyvtTFVmVhcMLU6v5fEb/ok4wyqtNU=
 golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/image v0.0.0-20181116024801-cd38e8056d9b h1:VHyIDlv3XkfCa5/a81uzaoDkHH4rr81Z62g+xlnO8uM=
 golang.org/x/image v0.0.0-20181116024801-cd38e8056d9b/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=
-golang.org/x/lint v0.0.0-20190409202823-959b441ac422 h1:QzoH/1pFpZguR8NrRHLcO6jKqfv2zpuSqZLgdm7ZmjI=
-golang.org/x/lint v0.0.0-20190409202823-959b441ac422/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
-golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190606173856-1492cefac77f/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20190606203320-7fc4e5ec1444/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2 h1:tW2bmiBqwgJj/UpqtC8EpXEZVYOwU0yG4iWbprSVAcs=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
-golang.org/x/tools v0.0.0-20190606174628-0139d5756a7d h1:CoaGYJ9a8IXms8Q/NUeypLWbStIszTH0IIwqBUkEB9g=
-golang.org/x/tools v0.0.0-20190606174628-0139d5756a7d/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
diff --git a/internal/transform/matrix.go b/internal/transform/matrix.go
@@ -21,11 +21,28 @@ func IdentityMatrix() Matrix {
 	return NewMatrix(1, 0, 0, 1, 0, 0)
 }
 
-// TranslationMatrix returns a matrix that translates by `tx`, `ty`.
+// TranslationMatrix returns a matrix that translates by `tx`,`ty`.
 func TranslationMatrix(tx, ty float64) Matrix {
 	return NewMatrix(1, 0, 0, 1, tx, ty)
 }
 
+// ScaleMatrix returns a matrix that scales by `x`,`y`.
+func ScaleMatrix(x, y float64) Matrix {
+	return NewMatrix(x, 0, 0, y, 0, 0)
+}
+
+// RotationMatrix returns a matrix that rotates by angle `angle`, specified in radians.
+func RotationMatrix(angle float64) Matrix {
+	c := math.Cos(angle)
+	s := math.Sin(angle)
+	return NewMatrix(c, s, -s, c, 0, 0)
+}
+
+// ShearMatrix returns a matrix that shears `x`,`y`.
+func ShearMatrix(x, y float64) Matrix {
+	return NewMatrix(1, y, x, 1, 0, 0)
+}
+
 // NewMatrix returns an affine transform matrix laid out in homogenous coordinates as
 //      a  b  0
 //      c  d  0
@@ -74,19 +91,37 @@ func (m Matrix) Mult(b Matrix) Matrix {
 	return m
 }
 
-// Translate appends a translation of `dx`,`dy` to `m`.
+// Translate appends a translation of `x`,`y` to `m`.
 // m.Translate(dx, dy) is equivalent to m.Concat(NewMatrix(1, 0, 0, 1, dx, dy))
-func (m *Matrix) Translate(dx, dy float64) {
-	m[6] += dx
-	m[7] += dy
-	m.clampRange()
+func (m *Matrix) Translate(x, y float64) {
+	m.Concat(TranslationMatrix(x, y))
 }
 
 // Translation returns the translation part of `m`.
 func (m *Matrix) Translation() (float64, float64) {
 	return m[6], m[7]
 }
 
+// Scale scales the current matrix by `x`,`y`.
+func (m *Matrix) Scale(x, y float64) {
+	m.Concat(ScaleMatrix(x, y))
+}
+
+// Rotate rotates the current matrix by angle `angle`, specified in radians.
+func (m *Matrix) Rotate(angle float64) {
+	m.Concat(RotationMatrix(angle))
+}
+
+// Shear shears the current matrix by `x',`y`.
+func (m *Matrix) Shear(x, y float64) {
+	m.Concat(ShearMatrix(x, y))
+}
+
+// Clone returns a copy of the current matrix.
+func (m *Matrix) Clone() Matrix {
+	return NewMatrix(m[0], m[1], m[3], m[4], m[6], m[7])
+}
+
 // Transform returns coordinates `x`,`y` transformed by `m`.
 func (m *Matrix) Transform(x, y float64) (float64, float64) {
 	xp := x*m[0] + y*m[1] + m[6]

diff --git a/internal/transform/point.go b/internal/transform/point.go
@@ -47,12 +47,25 @@ func (p Point) Rotate(theta float64) Point {
 	return Point{r * cos, r * sin}
 }
 
-// transformByMatrix mutates and transforms `p` by the affine transformation `m`.
-func (p *Point) transformByMatrix(m Matrix) {
-	p.X, p.Y = m.Transform(p.X, p.Y)
+// Distance returns the distance between `a` and `b`.
+func (a Point) Distance(b Point) float64 {
+	return math.Hypot(a.X-b.X, a.Y-b.Y)
+}
+
+// Interpolate does linear interpolation between point `a` and `b` for value `t`.
+func (a Point) Interpolate(b Point, t float64) Point {
+	return Point{
+		X: (1-t)*a.X + t*b.X,
+		Y: (1-t)*a.Y + t*b.Y,
+	}
 }
 
 // String returns a string describing `p`.
 func (p Point) String() string {
 	return fmt.Sprintf("(%.2f,%.2f)", p.X, p.Y)
 }
+
+// transformByMatrix mutates and transforms `p` by the affine transformation `m`.
+func (p *Point) transformByMatrix(m Matrix) {
+	p.X, p.Y = m.Transform(p.X, p.Y)
+}
diff --git a/render/image_device.go b/render/image_device.go
@@ -0,0 +1,106 @@
+/*
+ * This file is subject to the terms and conditions defined in
+ * file 'LICENSE.md', which is part of this source code package.
+ */
+
+package render
+
+import (
+	"errors"
+	"fmt"
+	"image"
+	"image/draw"
+	"image/jpeg"
+	"image/png"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/unidoc/unipdf/v3/model"
+	"github.com/unidoc/unipdf/v3/render/internal/context/imagerender"
+)
+
+// ImageDevice is used to render PDF pages to image targets.
+type ImageDevice struct {
+	renderer
+}
+
+// NewImageDevice returns a new image device.
+func NewImageDevice() *ImageDevice {
+	return &ImageDevice{}
+}
+
+// Render converts the specified PDF page into an image and returns the result.
+func (d *ImageDevice) Render(page *model.PdfPage) (image.Image, error) {
+	// Get page dimensions.
+	mbox, err := page.GetMediaBox()
+	if err != nil {
+		return nil, err
+	}
+
+	// Render page.
+	width, height := mbox.Llx+mbox.Width(), mbox.Lly+mbox.Height()
+
+	ctx := imagerender.NewContext(int(width), int(height))
+	if err := d.renderPage(ctx, page); err != nil {
+		return nil, err
+	}
+
+	// Apply crop box, if one exists.
+	img := ctx.Image()
+	if box := page.CropBox; box != nil {
+		// Calculate crop bounds and crop start position.
+		cropBounds := image.Rect(0, 0, int(box.Width()), int(box.Height()))
+		cropStart := image.Pt(int(box.Llx), int(height-box.Ury))
+
+		// Crop image.
+		cropImg := image.NewRGBA(cropBounds)
+		draw.Draw(cropImg, cropBounds, img, cropStart, draw.Src)
+		img = cropImg
+	}
+
+	return img, nil
+}
+
+// RenderToPath converts the specified PDF page into an image and saves the
+// result at the specified location.
+func (d *ImageDevice) RenderToPath(page *model.PdfPage, outputPath string) error {
+	image, err := d.Render(page)
+	if err != nil {
+		return err
+	}
+
+	extension := strings.ToLower(filepath.Ext(outputPath))
+	if extension == "" {
+		return errors.New("could not recognize output file type")
+	}
+
+	switch extension {
+	case ".png":
+		return savePNG(outputPath, image)
+	case ".jpg", ".jpeg":
+		return saveJPG(outputPath, image, 100)
+	}
+
+	return fmt.Errorf("unrecognized output file type: %s", extension)
+}
+
+func savePNG(path string, image image.Image) error {
+	file, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	return png.Encode(file, image)
+}
+
+func saveJPG(path string, image image.Image, quality int) error {
+	file, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	return jpeg.Encode(file, image, &jpeg.Options{Quality: quality})
+}
diff --git a/render/internal/context/const.go b/render/internal/context/const.go
@@ -0,0 +1,47 @@
+/*
+ * This file is subject to the terms and conditions defined in
+ * file 'LICENSE.md', which is part of this source code package.
+ */
+
+package context
+
+import "image/color"
+
+// FillRule represents the fill style used by a context instance.
+type FillRule int
+
+// Fill rules.
+const (
+	FillRuleWinding FillRule = iota
+	FillRuleEvenOdd
+)
+
+// LineCap represents the line cap style used by a context instance.
+type LineCap int
+
+// Line cap styles.
+const (
+	LineCapRound LineCap = iota
+	LineCapButt
+	LineCapSquare
+)
+
+// LineJoin represents the line join style used by a context instance.
+type LineJoin int
+
+// Line join styles.
+const (
+	LineJoinRound LineJoin = iota
+	LineJoinBevel
+)
+
+// Pattern represents a pattern which can be rendered by a context instance.
+type Pattern interface {
+	ColorAt(x, y int) color.Color
+}
+
+// Gradient represents a gradient pattern which can be rendered by a context instance.
+type Gradient interface {
+	Pattern
+	AddColorStop(offset float64, color color.Color)
+}