Added Area resizing. Everything mostly works, but not making things smaller...

area.go

@@ -21,12 +21,14 @@ import (
 // in platform-native ways is painful.
 // [Use TextArea instead, providing a TextAreaHandler.]
 // 
-// To facilitate development and debugging, for the time being, Areas have a fixed size of 320x240 and only work on GTK+.
+// To facilitate development and debugging, for the time being, Areas only work on GTK+.
 type Area struct {
 	lock			sync.Mutex
 	created		bool
 	sysData		*sysData
 	handler		AreaHandler
+	initwidth		int
+	initheight		int
 }
 
 // AreaHandler represents the events that an Area should respond to.
@@ -210,18 +212,34 @@ const (
 	// TODO add Super
 )
 
-// NewArea creates a new Area.
+// NewArea creates a new Area with the given size and handler.
 // It panics if handler is nil.
-func NewArea(handler AreaHandler) *Area {
+func NewArea(width int, height int, handler AreaHandler) *Area {
 	if handler == nil {
 		panic("handler passed to NewArea() must not be nil")
 	}
 	return &Area{
 		sysData:		mksysdata(c_area),
 		handler:		handler,
+		initwidth:		width,
+		initheight:		height,
 	}
 }
 
+// SetSize sets the Area's internal drawing size.
+// It has no effect on the actual control size.
+func (a *Area) SetSize(width int, height int) {
+	a.lock.Lock()
+	defer a.lock.Unlock()
+
+	if a.created {
+		a.sysData.setAreaSize(width, height)
+		return
+	}
+	a.initwidth = width
+	a.initheight = height
+}
+
 func (a *Area) make(window *sysData) error {
 	a.lock.Lock()
 	defer a.lock.Unlock()
@@ -231,6 +249,7 @@ func (a *Area) make(window *sysData) error {
 	if err != nil {
 		return err
 	}
+	a.sysData.setAreaSize(a.initwidth, a.initheight)
 	a.created = true
 	return nil
 }

area_unix.go

@@ -24,7 +24,7 @@ import "C"
 
 func gtkAreaNew() *gtkWidget {
 	drawingarea := C.gtk_drawing_area_new()
-	C.gtk_widget_set_size_request(drawingarea, 320, 240)
+	C.gtk_widget_set_size_request(drawingarea, 100, 100)		// default initial size (TODO do we need it?); use C. to avoid casting drawingarea
 	// we need to explicitly subscribe to mouse events with GtkDrawingArea
 	C.gtk_widget_add_events(drawingarea,
 		C.GDK_BUTTON_PRESS_MASK | C.GDK_BUTTON_RELEASE_MASK | C.GDK_POINTER_MOTION_MASK | C.GDK_BUTTON_MOTION_MASK)

gtkcalls_unix.go

@@ -217,3 +217,7 @@ func gtk_progress_bar_set_fraction(w *gtkWidget, percent int) {
 func gtk_progress_bar_pulse(w *gtkWidget) {
 	C.gtk_progress_bar_pulse(togtkprogressbar(w))
 }
+
+func gtk_widget_queue_draw(widget *gtkWidget) {
+	C.gtk_widget_queue_draw(togtkwidget(widget))
+}

sysdata.go

@@ -76,6 +76,9 @@ func (c *cSysData) setProgress(int) {
 func (c *cSysData) len() int {
 	panic(runtime.GOOS + " sysData does not define len()")
 }
+func (c *cSysData) setAreaSize(int, int) {
+	panic(runtime.GOOS + " sysData does not define setAreaSize()")
+}
 
 // signal sends the event signal. This raise is done asynchronously to avoid deadlocking the UI task.
 // Thanks skelterjohn for this techinque: if we can't queue any more events, drop them

sysdata_unix.go

@@ -350,3 +350,15 @@ func (s *sysData) len() int {
 	}
 	return <-ret
 }
+
+func (s *sysData) setAreaSize(width int, height int) {
+	ret := make(chan struct{})
+	defer close(ret)
+	uitask <- func() {
+		c := gtkAreaGetControl(s.widget)
+		gtk_widget_set_size_request(c, width, height)
+		gtk_widget_queue_draw(c)		// force repaint (TODO doesn't have an effect when shrinking?)
+		ret <- struct{}{}
+	}
+	<-ret
+}

test/main.go

@@ -10,6 +10,7 @@ import (
 	_ "image/png"
 	"bytes"
 	"time"
+	"strconv"
 	. "github.com/andlabs/ui"
 )
 
@@ -158,13 +159,25 @@ func areaTest() {
 	img := image.NewNRGBA(ximg.Bounds())
 	draw.Draw(img, img.Rect, ximg, image.ZP, draw.Over)
 	w := NewWindow("Area Test", 100, 100)
-	a := NewArea(&areaHandler{
+	a := NewArea(320, 240, &areaHandler{
 		img:		img,
 	})
 	timedisp := NewLabel("")
 	timechan := time.Tick(time.Second)
+	widthbox := NewLineEdit("320")
+	heightbox := NewLineEdit("240")
+	resize := NewButton("Resize")
+	sizeStack := NewHorizontalStack(widthbox, heightbox, resize)
+	sizeStack.SetStretchy(0)
+	sizeStack.SetStretchy(1)
+	sizeStack.SetStretchy(2)
+	sizeStack = NewHorizontalStack(sizeStack, Space(), Space())
+	sizeStack.SetStretchy(0)
+	sizeStack.SetStretchy(1)
+	sizeStack.SetStretchy(2)
 	layout := NewVerticalStack(a,
-		NewHorizontalStack(timedisp))
+		NewHorizontalStack(timedisp),
+		sizeStack)
 	layout.SetStretchy(0)
 	err = w.Open(layout)
 	if err != nil {
@@ -176,6 +189,13 @@ func areaTest() {
 			return
 		case t := <-timechan:
 			timedisp.SetText(t.String())
+		case <-resize.Clicked:
+			width, err := strconv.Atoi(widthbox.Text())
+			if err != nil { println(err); continue }
+			height, err := strconv.Atoi(heightbox.Text())
+			if err != nil { println(err); continue }
+println(width, height)
+			a.SetSize(width, height)
 		}
 	}
 }