Implemented ProgressBar on Mac OS X.

basicctrls_darwin.m

@@ -10,6 +10,7 @@
 #define toNSWindow(x) ((NSWindow *) (x))
 #define toNSBox(x) ((NSBox *) (x))
 #define toNSTextView(x) ((NSTextView *) (x))
+#define toNSProgressIndicator(x) ((NSProgressIndicator *) (x))
 
 @interface goControlDelegate : NSObject <NSTextFieldDelegate> {
 @public
@@ -271,3 +272,31 @@ void textboxSetText(id tv, char *text)
 {
 	[toNSTextView(tv) setString:[NSString stringWithUTF8String:text]];
 }
+
+id newProgressBar(void)
+{
+	NSProgressIndicator *pi;
+
+	pi = [[NSProgressIndicator alloc] initWithFrame:NSZeroRect];
+	[pi setStyle:NSProgressIndicatorBarStyle];
+	[pi setControlSize:NSRegularControlSize];
+	[pi setControlTint:NSDefaultControlTint];
+	[pi setBezeled:YES];
+	[pi setDisplayedWhenStopped:YES];
+	[pi setUsesThreadedAnimation:YES];
+	[pi setIndeterminate:NO];
+	[pi setMinValue:0];
+	[pi setMaxValue:100];
+	[pi setDoubleValue:0];
+	return (id) pi;
+}
+
+intmax_t progressbarPercent(id pbar)
+{
+	return (intmax_t) [toNSProgressIndicator(pbar) doubleValue];
+}
+
+void progressbarSetPercent(id pbar, intmax_t percent)
+{
+	[toNSProgressIndicator(pbar) setDoubleValue:((double) percent)];
+}

objc_darwin.h

@@ -82,6 +82,9 @@ extern void groupSetText(id, char *);
 extern id newTextbox(void);
 extern char *textboxText(id);
 extern void textboxSetText(id, char *);
+extern id newProgressBar(void);
+extern intmax_t progressbarPercent(id);
+extern void progressbarSetPercent(id, intmax_t);
 
 /* container_darwin.m */
 extern id newContainerView(void *);

progressbar_darwin.go

@@ -0,0 +1,31 @@
+// 4 november 2014
+
+package ui
+
+import (
+	"fmt"
+)
+
+// #include "objc_darwin.h"
+import "C"
+
+type progressbar struct {
+	*controlSingleObject
+}
+
+func newProgressBar() ProgressBar {
+	return &progressbar{
+		controlSingleObject:		newControlSingleObject(C.newProgressBar()),
+	}
+}
+
+func (p *progressbar) Percent() int {
+	return int(C.progressbarPercent(p.id))
+}
+
+func (p *progressbar) SetPercent(percent int) {
+	if percent < 0 || percent > 100 {
+		panic(fmt.Errorf("given ProgressBar percentage %d out of range", percent))
+	}
+	C.progressbarSetPercent(p.id, C.intmax_t(percent))
+}