func New(w, h vg.Length) *Canvas {
buf := new(bytes.Buffer)
c := &Canvas{
svg: svgo.New(buf),
w: w,
h: h,
buf: buf,
ht: w.Points(),
stk: []context{context{}},
}
// This is like svg.Start, except it uses floats
// and specifies the units.
fmt.Fprintf(buf, `<?xml version="1.0"?>
<!-- Generated by SVGo and Plotinum VG -->
<svg width="%.*gin" height="%.*gin"
xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink">`+"\n",
pr, w/vg.Inch,
pr, h/vg.Inch,
)
// Swap the origin to the bottom left.
// This must be matched with a </g> when saving,
// before the closing </svg>.
c.svg.Gtransform(fmt.Sprintf("scale(1, -1) translate(0, -%.*g)", pr, h.Dots(DPI)))
vg.Initialize(c)
return c
}
// NewImage returns a new image canvas
// that draws to the given image. The
// minimum point of the given image
// should probably be 0,0.
func NewImage(img draw.Image, name string) (*Canvas, error) {
w := float64(img.Bounds().Max.X - img.Bounds().Min.X)
h := float64(img.Bounds().Max.Y - img.Bounds().Min.Y)
X, err := xgbutil.NewConn()
if err != nil {
return nil, err
}
keybind.Initialize(X)
ximg := xgraphics.New(X, image.Rect(0, 0, int(w), int(h)))
err = ximg.CreatePixmap()
if err != nil {
return nil, err
}
painter := NewPainter(ximg)
gc := draw2dimg.NewGraphicContextWithPainter(ximg, painter)
gc.SetDPI(dpi)
gc.Scale(1, -1)
gc.Translate(0, -h)
wid := ximg.XShowExtra(name, true)
go func() {
xevent.Main(X)
}()
c := &Canvas{
Canvas: vgimg.NewWith(vgimg.UseImageWithContext(img, gc)),
x: X,
ximg: ximg,
wid: wid,
}
vg.Initialize(c)
return c, nil
}
// New creates a new PDF Canvas.
func New(w, h vg.Length) *Canvas {
c := &Canvas{
doc: pdf.New(),
w: w,
h: h,
lineVisible: true,
}
c.page = c.doc.NewPage(unit(w), unit(h))
vg.Initialize(c)
return c
}
// NewTitle returns a new Canvas with the given title string.
func NewTitle(w, h vg.Length, title string) *Canvas {
c := &Canvas{
stk: []ctx{ctx{}},
w: w,
h: h,
buf: new(bytes.Buffer),
}
c.buf.WriteString("%%!PS-Adobe-3.0 EPSF-3.0\n")
c.buf.WriteString("%%Creator github.com/skiesel/plot/vg/vgeps\n")
c.buf.WriteString("%%Title: " + title + "\n")
c.buf.WriteString(fmt.Sprintf("%%%%BoundingBox: 0 0 %.*g %.*g\n",
pr, w.Dots(DPI),
pr, h.Dots(DPI)))
c.buf.WriteString(fmt.Sprintf("%%%%CreationDate: %s\n", time.Now()))
c.buf.WriteString("%%Orientation: Portrait\n")
c.buf.WriteString("%%EndComments\n")
c.buf.WriteString("\n")
vg.Initialize(c)
return c
}
// NewWith returns a new image canvas created according to the specified
// options. The currently accepted options are UseWH,
// UseDPI, UseImage, and UseImageWithContext.
// Each of the options specifies the size of the canvas (UseWH, UseImage),
// the resolution of the canvas (UseDPI), or both (useImageWithContext).
// If size or resolution are not specified, defaults are used.
// It panics if size and resolution are overspecified (i.e., too many options are
// passed).
func NewWith(o ...option) *Canvas {
c := new(Canvas)
var g uint32
for _, opt := range o {
f := opt(c)
if g&f != 0 {
panic("incompatible options")
}
g |= f
}
if c.dpi == 0 {
c.dpi = DefaultDPI
}
if c.w == 0 { // h should also == 0.
if c.img == nil {
c.w = DefaultWidth
c.h = DefaultHeight
} else {
w := float64(c.img.Bounds().Max.X - c.img.Bounds().Min.X)
h := float64(c.img.Bounds().Max.Y - c.img.Bounds().Min.Y)
c.w = vg.Length(w/float64(c.dpi)) * vg.Inch
c.h = vg.Length(h/float64(c.dpi)) * vg.Inch
}
}
if c.img == nil {
w := c.w / vg.Inch * vg.Length(c.dpi)
h := c.h / vg.Inch * vg.Length(c.dpi)
c.img = draw.Image(image.NewRGBA(image.Rect(0, 0, int(w+0.5), int(h+0.5))))
}
if c.gc == nil {
h := float64(c.img.Bounds().Max.Y - c.img.Bounds().Min.Y)
c.gc = draw2dimg.NewGraphicContext(c.img)
c.gc.SetDPI(c.dpi)
c.gc.Scale(1, -1)
c.gc.Translate(0, -h)
}
draw.Draw(c.img, c.img.Bounds(), image.White, image.ZP, draw.Src)
c.color = []color.Color{color.Black}
vg.Initialize(c)
return c
}