added test for concurrent text drawing

sync_test.go

@@ -0,0 +1,97 @@
+// See also test_test.go
+
+package draw2d_test
+
+import (
+	"fmt"
+	"github.com/golang/freetype/truetype"
+	"github.com/llgcode/draw2d"
+	"github.com/llgcode/draw2d/draw2dimg"
+	"github.com/llgcode/draw2d/draw2dkit"
+	"image"
+	"io/ioutil"
+	"path/filepath"
+	"sync"
+	"testing"
+)
+
+func TestSync(t *testing.T) {
+	ch := make(chan int)
+	limit := 200
+	for i := 0; i < limit; i++ {
+		go Draw(i, ch)
+	}
+
+	for i := 0; i < limit; i++ {
+		counter := <-ch
+		t.Logf("Goroutine %d returned\n", counter)
+	}
+}
+
+func Draw(i int, ch chan<- int) {	
+	draw2d.SetFontCache(testCache)
+
+	// Draw a rounded rectangle using default colors
+	dest := image.NewRGBA(image.Rect(0, 0, 297, 210.0))
+	gc := draw2dimg.NewGraphicContext(dest)
+
+	draw2dkit.RoundedRectangle(gc, 5, 5, 135, 95, 10, 10)
+	gc.FillStroke()
+
+	// Set the fill text color to black
+	gc.SetFillColor(image.Black)
+	gc.SetFontSize(14)
+
+	// Display Hello World dimensions
+	x1, y1, x2, y2 := gc.GetStringBounds("Hello world")
+	gc.FillStringAt(fmt.Sprintf("%.2f %.2f %.2f %.2f", x1, y1, x2, y2), 0, 0)
+
+	ch <- i
+}
+
+//testFontCache closely follows draw2d's defaultFontCache
+type testFontCache struct {
+	fonts  map[string]*truetype.Font
+	folder string
+	namer  draw2d.FontFileNamer
+}
+
+func (cache *testFontCache) Load(fontData draw2d.FontData) (font *truetype.Font, err error) {
+	if font = cache.fonts[cache.namer(fontData)]; font != nil {
+		return font, nil
+	}
+
+	var data []byte
+	var file = cache.namer(fontData)
+
+	if data, err = ioutil.ReadFile(filepath.Join(cache.folder, file)); err != nil {
+		return
+	}
+
+	if font, err = truetype.Parse(data); err != nil {
+		return
+	}
+
+	var mu sync.Mutex
+	mu.Lock()
+	cache.fonts[file] = font
+	mu.Unlock()
+	return
+}
+
+func (cache *testFontCache) Store(fontData draw2d.FontData, font *truetype.Font) {
+	var mu sync.Mutex
+	mu.Lock()
+	cache.fonts[cache.namer(fontData)] = font
+	mu.Unlock()
+}
+
+var (
+	testFonts = &testFontCache{
+		fonts:  make(map[string]*truetype.Font),
+		folder: "./resource/font",
+		namer:  draw2d.FontFileName,
+	}
+
+	testCache draw2d.FontCache = testFonts
+)