diff options
Diffstat (limited to 'area.go')
| -rw-r--r-- | area.go | 130 |
1 files changed, 128 insertions, 2 deletions
@@ -2,13 +2,139 @@ package ui +import ( + "unsafe" +) + // #include "ui.h" import "C" // no need to lock this; only the GUI thread can access it var areas = make(map[*C.uiArea]*Area) -// TODO. +// Area is a Control that represents a blank canvas that a program +// can draw on as it wishes. Areas also receive keyboard and mouse +// events, and programs can react to those as they see fit. Drawing +// and event handling are handled through an instance of a type +// that implements AreaHandler that every Area has; see AreaHandler +// for details. +// +// There are two types of areas. Non-scrolling areas are rectangular +// and have no scrollbars. Programs can draw on and get mouse +// events from any point in the Area, and the size of the Area is +// decided by package ui itself, according to the layout of controls +// in the Window the Area is located in and the size of said Window. +// There is no way to query the Area's size or be notified when its +// size changes; instead, you are given the area size as part of the +// draw and mouse event handlers, for use solely within those +// handlers. +// +// Scrolling areas have horziontal and vertical scrollbars. The amount +// that can be scrolled is determined by the area's size, which is +// decided by the programmer (both when creating the Area and by +// a call to SetSize). Only a portion of the Area is visible at any time; +// drawing and mouse events are automatically adjusted to match +// what portion is visible, so you do not have to worry about scrolling +// in your event handlers. AreaHandler has more information. +// +// The internal coordinate system of an Area is points, which are +// floating-point and device-independent. For more details, see +// AreaHandler. type Area struct { - Control + c *C.uiControl + a *C.uiArea + + ah *C.uiAreaHandler + + scrolling bool +} + +// NewArea creates a new non-scrolling Area. +func NewArea(handler AreaHandler) *Area { + a := new(Area) + a.scrolling = false + a.ah = registerAreaHandler(handler) + + a.a = C.uiNewArea(a.ah) + a.c = (*C.uiControl)(unsafe.Pointer(a.a)) + + areas[a.a] = a + + return a +} + +// NewScrollingArea creates a new scrolling Area of the given size, +// in points. +func NewScrollingArea(handler AreaHandler, width int, height int) *Area { + a := new(Area) + a.scrolling = true + a.ah = registerAreaHandler(handler) + + a.a = C.uiNewScrollingArea(a.ah, C.intmax_t(width), C.intmax_t(height)) + a.c = (*C.uiControl)(unsafe.Pointer(a.a)) + + areas[a.a] = a + + return a +} + +// Destroy destroys the Area. +func (a *Area) Destroy() { + delete(areas, a.a) + C.uiControlDestroy(a.c) + unregisterAreaHandler(a.ah) +} + +// LibuiControl returns the libui uiControl pointer that backs +// the Area. This is only used by package ui itself and should +// not be called by programs. +func (a *Area) LibuiControl() uintptr { + return uintptr(unsafe.Pointer(a.c)) +} + +// Handle returns the OS-level handle associated with this Area. +// On Windows this is an HWND of a libui-internal class. +// On GTK+ this is a pointer to a GtkScrolledWindow with a +// GtkViewport as its child. The child of the viewport is the +// GtkDrawingArea that provides the Area itself. +// On OS X this is a pointer to a NSScrollView whose document view +// is the NSView that provides the Area itself. +func (a *Area) Handle() uintptr { + return uintptr(C.uiControlHandle(a.c)) +} + +// Show shows the Area. +func (a *Area) Show() { + C.uiControlShow(a.c) +} + +// Hide hides the Area. +func (a *Area) Hide() { + C.uiControlHide(a.c) +} + +// Enable enables the Area. +func (a *Area) Enable() { + C.uiControlEnable(a.c) +} + +// Disable disables the Area. +func (a *Area) Disable() { + C.uiControlDisable(a.c) +} + +// SetSize sets the size of a scrolling Area to the given size, in points. +// SetSize panics if called on a non-scrolling Area. +func (a *Area) SetSize(width int, height int) { + if !a.scrolling { + panic("attempt to call SetSize on non-scrolling Area") + } + C.uiAreaSetSize(a.a, C.intmax_t(width), C.intmax_t(height)) +} + +// QueueRedrawAll queues the entire Area for redraw. +// The Area is not redrawn before this function returns; it is +// redrawn when next possible. +func (a *Area) QueueRedrawAll() { + C.uiAreaQueueRedrawAll(a.a) } |