add sample: frameimage

samples/frameimage/frameimage.go

@@ -0,0 +1,59 @@
+// Copyright 2010 The draw2d Authors. All rights reserved.
+// created: 21/11/2010 by Laurent Le Goff, Stani Michiels
+
+// Package frameimage centers a png image and rotates it.
+package frameimage
+
+import (
+	"math"
+
+	"github.com/llgcode/draw2d"
+	"github.com/llgcode/draw2d/samples"
+)
+
+// Main draws the image frame and returns the filename.
+// This should only be used during testing.
+func Main(gc draw2d.GraphicContext, ext string) (string, error) {
+	// Margin between the image and the frame
+	const margin = 30
+	// Line width od the frame
+	const lineWidth = 3
+
+	// Gopher image
+	gopher := samples.Resource("image", "gopher.png", ext)
+
+	// Draw gopher
+	err := Draw(gc, gopher, 297, 210, margin, lineWidth)
+
+	// Return the output filename
+	return samples.Output("frameimage", ext), err
+}
+
+// Draw the image frame with certain parameters.
+func Draw(gc draw2d.GraphicContext, png string,
+	dw, dh, margin, lineWidth float64) error {
+	// Draw frame
+	draw2d.RoundRect(gc, lineWidth, lineWidth,
+		dw-lineWidth, dh-lineWidth, 100, 100)
+	gc.SetLineWidth(lineWidth)
+	gc.FillStroke()
+
+	// load the source image
+	source, err := draw2d.LoadFromPngFile(png)
+	if err != nil {
+		return err
+	}
+	// Size of source image
+	sw, sh := float64(source.Bounds().Dx()), float64(source.Bounds().Dy())
+	// Draw image to fit in the frame
+	// TODO Seems to have a transform bug here on draw image
+	scale := math.Min((dw-margin*2)/sw, (dh-margin*2)/sh)
+	gc.Save()
+	gc.Translate((dw-sw*scale)/2, (dh-sh*scale)/2)
+	gc.Scale(scale, scale)
+	gc.Rotate(0.2)
+
+	gc.DrawImage(source)
+	gc.Restore()
+	return nil
+}