CWidget Class Reference

Description

Base class for all widgets.

This class is not abstract, but by itself allows to display arbitrary SDL surfaces.

Definition at line 94 of file ui_screen.H.

#include "ui_screen.H"

Inheritance diagram for CWidget:

Public Member Functions
Setup ...
void	Set (SDL_Surface *_surf, int x0, int y0)
void	SetArea (SDL_Rect _area)
SDL_Rect *	GetArea ()
class CScreen *	GetScreen ()
bool	IsOnScreen (class CScreen *_screen)
class CCanvas *	GetCanvas ()
Coordinate transformations (screen <-> render <-> local) ...
void	LocalToScreenCoords (int *x, int *y)
void	ScreenToLocalCoords (int *x, int *y)
void	GetMouseEventPos (SDL_Event *ev, int *x, int *y)
Surface-oriented drawing ...
This class itself is able to display a non-interactive surface.
void	SetSurface (SDL_Surface *_surface)
	Set the static surface to display. The caller stays owner of surface, must not delete it as long as it is set here. The surface dimensions must match 'area'.
virtual SDL_Surface *	GetSurface ()
	Get an up-to-date surface or 'NULL' if none is available.
Texture-oriented drawing...
void	GetRenderArea (SDL_Rect *ra)
	Transpose 'area' to the current screen coordinates to be passed to all SDL rendering functions.
virtual SDL_Texture *	GetTexture ()
	Return an up-to-date texture. More...
void	SetTextureBlendMode (SDL_BlendMode _sdlBlendMode)
	Set the blend mode for the texture created by the default implementation of GetTexture(). The default is SDL_BLENDMODE_NONE.
virtual void	Render (SDL_Renderer *ren)
	Render this widget. More...
void	ClearTexture ()
	Clear the internally cached texture object to save memory.
Event handling ...
virtual bool	HandleEvent (SDL_Event *ev)
	Handle an event and return 'true' if the event was consumed and is to be ignored by later widgets.

Protected Member Functions
Change management...
The following methods trigger a redrawing at next occasion. The following conventions must be satisfied by this and all derived classes: On a change, the most specialized 'Change*()' function is called, which may in turn call other 'Change*()' methods. All public methods call their change methods => no need to make these public. The 'Change*()' methods must be very fast (i.e. O(1)) in execution, at least if invoked repeatedly.
void	ChangedSurface ()
	Mark (only) the surface as changed to trigger a redrawing at next occasion.
void	Changed ()
	Anything may have changed: Trigger a redrawing at next occasion.

Friends
class	CScreen
class	CCanvas

Member Function Documentation

GetTexture()

virtual SDL_Texture* CWidget::GetTexture ( )

virtual

Return an up-to-date texture.

The default implementation maintains an internal texture that is updated based on the surface set by SetSurface(). Widgets that generate SDL texture objects directly may override this method.

Render()

virtual void CWidget::Render ( SDL_Renderer *  ren )

virtual

Render this widget.

The default implementation uses the 'GetTexture()' method above. By overriding this method it is possible to define widgets with a custom SDL rendering procedure, which may be more efficient than preparing a single texture containing the complete widget.

It is allowed to pass 'ren == NULL', in which case all textures and internal data structures are (re-)calculated, but nothing is actually rendered.

Reimplemented in CInputLine, CMenu, CListbox, CCursorWidget, and CCanvas.

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The documentation for this class was generated from the following file:

• wallclock/ui_screen.H