org.gnu.gnome

Class Canvas

public class Canvas extends Layout

You can use the GnomeCanvas widget to draw figures, display graphics, position widgets, and more.

Constructor Summary
	Canvas(boolean useAntialiased) Constructs a new Canvas.
	Canvas() Construct a new Canvas.
	Canvas(Handle handle) Constructs a new Canvas object form a native resource.

Method Summary
static Canvas	getCanvas(Handle handle) Internal static factory method to be used by Java-Gnome only.
boolean	getCenterScrollRegion()
Color	getColor(String spec) Takes a string specification for a color and allocates it into the specified GdkColor.
long	getColorPixel(int rgba) Allocates a color from the RGB value passed into this function.
CanvasItem	getCurrentCanvasItem() The item containing the mouse pointer, or NULL if none.
RgbDither	getDither() Returns the dither mode of an antialiased canvas.
CanvasItem	getFocusedCanvasItem() The currently focused item, or NULL if none.
CanvasItem	getGrabbedCanvasItem() The item that holds a pointer grab, or NULL if none.
CanvasItem	getItemAt(double x, double y) Returns the item that is at the specified position in world coordinates, or NULL if no item is there.
double	getPixelsPerUnit() Scaling factor to be used for display.
CanvasGroup	getRoot() Returns the root canvas item group of the canvas
double	getScrollOffsetX() Returns the horizontal scroll offset of the canvas in canvas pixel coordinates.
double	getScrollOffsetY() Returns the vertical scroll offset of the canvas in canvas pixel coordinates.
double	getScrollX1() The x1 coordinate of the scrolling region.
double	getScrollX2() The x2 coordinate of the scrolling region.
double	getScrollY1() The y1 coordinate of the scrolling region.
double	getScrollY2() The y2 coordinate of the scrolling region.
static Type	getType() Retrieve the runtime type used by the GLib library.
void	requestRedraw(int x1, int y1, int x2, int y2)
void	scrollTo(int cx, int cy) Scrolls the canvas to the specified offsets, given in canvas pixel coordinates.
void	setCenterScrollRegion(boolean center)
void	setDither(RgbDither dither) Controls the dithering used when the canvas renders.
void	setPixelsPerUnit(double n) Sets the number of pixels that correspond to one unit in world coordinates.
void	setScrollRegion(double x1, double y1, double x2, double y2) Convenience method to set all 4 coordinates of the scroll region at once.
void	setScrollX1(double x1) Set the scroll region's X1 coordinate.
void	setScrollX2(double x2) Set the scroll region's X2 coordinate.
void	setScrollY1(double y1) Set the scroll region's Y1 coordinate.
void	setScrollY2(double y2) Set the scroll region's Y2 coordinate.
void	update() Requests that the canvas be repainted immediately instead of during the idle loop.
double	windowToWorldX(double winx)
double	windowToWorldY(double winy)
double	worldToWindowX(double worldx)
double	worldToWindowY(double worldy)

Constructor Detail

Canvas

public Canvas(boolean useAntialiased)

Constructs a new Canvas.

Canvas

public Canvas()

Deprecated:

Construct a new Canvas.

Canvas

public Canvas(Handle handle)

Constructs a new Canvas object form a native resource.

Parameters: handle The handle to the native resource.

Method Detail

getCanvas

public static Canvas getCanvas(Handle handle)

Internal static factory method to be used by Java-Gnome only.

getCenterScrollRegion

public boolean getCenterScrollRegion()

getColor

public Color getColor(String spec)

Takes a string specification for a color and allocates it into the specified GdkColor.

Parameters: spec The color to allocate.

getColorPixel

public long getColorPixel(int rgba)

Allocates a color from the RGB value passed into this function.

Parameters: rgba The RGB value.

getCurrentCanvasItem

public CanvasItem getCurrentCanvasItem()

The item containing the mouse pointer, or NULL if none.

getDither

public RgbDither getDither()

Returns the dither mode of an antialiased canvas. Only applicable to antialiased canvases - ignored by non-antialiased convases.

getFocusedCanvasItem

public CanvasItem getFocusedCanvasItem()

The currently focused item, or NULL if none.

getGrabbedCanvasItem

public CanvasItem getGrabbedCanvasItem()

The item that holds a pointer grab, or NULL if none.

getItemAt

public CanvasItem getItemAt(double x, double y)

Returns the item that is at the specified position in world coordinates, or NULL if no item is there.

Parameters: x The horizontal coordinate. y The vertical coordinate.

getPixelsPerUnit

public double getPixelsPerUnit()

Scaling factor to be used for display.

getRoot

public CanvasGroup getRoot()

Returns the root canvas item group of the canvas

getScrollOffsetX

public double getScrollOffsetX()

Returns the horizontal scroll offset of the canvas in canvas pixel coordinates.

Returns: The scroll offset x coordinate.

getScrollOffsetY

public double getScrollOffsetY()

Returns the vertical scroll offset of the canvas in canvas pixel coordinates.

Returns: The scroll offset y coordinate.

getScrollX1

public double getScrollX1()

The x1 coordinate of the scrolling region.

getScrollX2

public double getScrollX2()

The x2 coordinate of the scrolling region.

getScrollY1

public double getScrollY1()

The y1 coordinate of the scrolling region.

getScrollY2

public double getScrollY2()

The y2 coordinate of the scrolling region.

getType

public static Type getType()

Retrieve the runtime type used by the GLib library.

requestRedraw

public void requestRedraw(int x1, int y1, int x2, int y2)

scrollTo

public void scrollTo(int cx, int cy)

Scrolls the canvas to the specified offsets, given in canvas pixel coordinates.

Parameters: cx Horizontal coordinate. cy Vertical coordinate.

setCenterScrollRegion

public void setCenterScrollRegion(boolean center)

setDither

public void setDither(RgbDither dither)

Controls the dithering used when the canvas renders. Only applicable to antialiased canvases - ignored by non-antialiased canvases.

setPixelsPerUnit

public void setPixelsPerUnit(double n)

Sets the number of pixels that correspond to one unit in world coordinates.

Parameters: n The number of pixels

setScrollRegion

public void setScrollRegion(double x1, double y1, double x2, double y2)

Convenience method to set all 4 coordinates of the scroll region at once.

Parameters: x1 First horizontal coordinate. y1 First vertical coordinate. x2 Second horizontal coordinate. y2 Second vertical coordinate.

setScrollX1

public void setScrollX1(double x1)

Set the scroll region's X1 coordinate.

Parameters: x1

setScrollX2

public void setScrollX2(double x2)

Set the scroll region's X2 coordinate.

Parameters: x2

setScrollY1

public void setScrollY1(double y1)

Set the scroll region's Y1 coordinate.

Parameters: y1

setScrollY2

public void setScrollY2(double y2)

Set the scroll region's Y2 coordinate.

Parameters: y2

update

public void update()

Requests that the canvas be repainted immediately instead of during the idle loop.

windowToWorldX

public double windowToWorldX(double winx)

windowToWorldY

public double windowToWorldY(double winy)

worldToWindowX

public double worldToWindowX(double worldx)

worldToWindowY

public double worldToWindowY(double worldy)