Added portable parts of ProgressBar.

progressbar.go

@@ -0,0 +1,64 @@
+// 25 february 2014
+package ui
+
+import (
+	// ...
+)
+
+// A ProgressBar is a horizontal rectangle that fills up from left to right to indicate the progress of a long-running task.
+// This progress is typically a percentage, so within the range [0,100].
+// Alternatively, a progress bar can be "indeterminate": it indicates progress is being made, but is unclear as to how much.
+// The presentation of indeterminate progress bars is system-specific (for instance, on Windows and many GTK+ skins, this is represented by a small chunk of progress going back and forth across the width of the bar).
+type ProgressBar struct {
+	lock		sync.Mutex
+	created	bool
+	sysData	*sysData
+	initProg	int
+}
+
+// NewProgressBar creates a new ProgressBar.
+func NewProgressBar() *ProgressBar {
+	return &ProgressBar{
+		sysData:	mksysdata(c_progressbar),
+	}
+}
+
+// SetProgress sets the currently indicated progress amount on the ProgressBar. If this amount is outside the range [0,100] (ideally -1), the progress bar is indeterminate.
+func (p *ProgressBar) SetProgress(percent int) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	if p.created {
+		p.sysData.setProgress(percent)
+		return
+	}
+	p.initProg = percent
+}
+
+func (p *ProgressBar) make(window *sysData) error {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	err := p.sysData.make("", window)
+	if err != nil {
+		return err
+	}
+	p.sysData.setProgress(p.initProg)
+	p.created = true
+	return nil
+}
+
+func (p *ProgressBar) setRect(x int, y int, width int, height int) error {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	return p.sysData.setRect(x, y, width, height)
+}
+
+func (p *ProgressBar) preferredSize() (width int, height int, err error) {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+
+	width, height = p.sysData.preferredSize()
+	return
+}

sysdata.go

@@ -64,6 +64,9 @@ func (c *cSysData) delete(int) error {
 func (c *cSysData) preferredSize() (int, int) {
 	panic(runtime.GOOS + " sysData does not define preferredSize()")
 }
+func (c *cSysData) setProgress(int) {
+	panic(runtime.GOOS + " sysData does not define setProgress()")
+}
 
 // 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
@@ -86,6 +89,7 @@ const (
 	c_lineedit
 	c_label
 	c_listbox
+	c_progressbar
 	nctypes
 )