Canvas Class Reference

Class for painting objects and drawing in a windows. More...

Inherited by FreeCanvas, PaintCanvas, and UpdateCanvas.

List of all members.

Public Member Functions
int	drawText (const SmartUtil::tstring &text, const SmartWin::Rectangle &rect, unsigned format)
	Draws given string within given Rectangle.
void	ellipse (const SmartWin::Rectangle &rect)
	Draws an ellipse in the Device Context.
void	ellipse (int left, int top, int right, int bottom)
	Draws an ellipse in the Device Context.
bool	extFloodFill (int x, int y, COLORREF color, bool fillTilColorFound)
	parameter.
void	extTextOut (const SmartUtil::tstring &text, unsigned x, unsigned y)
	Draws given text inside given Rectangle.
void	fillRectangle (const SmartWin::Rectangle &rect, Brush &brush)
	Fills a Rectangle in the Device Context with the given brush.
void	fillRectangle (int left, int top, int right, int bottom, Brush &brush)
	Fills a Rectangle in the Device Context with the given brush.
COLORREF	getBkColor ()
	Gets the background color for the this Canvas.
HDC	getDc ()
	Returns the Device Context for the Canvas.
int	getDeviceCaps (int nIndex)
	Gets the device capabilities.
COLORREF	getPixel (const Point &coord)
	Returns the pixel's color at given point.
COLORREF	getPixel (int x, int y)
	Returns the pixel's color at (x,y).
COLORREF	getSysColor (int index)
	Gets the color for an system display object.
void	line (const SmartWin::Rectangle &rect)
	Draws a line around a Rectangle without filling it.
void	line (const Point &start, const Point &end)
	Draws a line from Start to End in the Device Context.
void	line (int xStart, int yStart, int xEnd, int yEnd)
	Draws a line in the Device Context.
void	lineTo (const Point &coord)
	Draws a line from the current position to a specific Point.
void	lineTo (int x, int y)
	Draws a line from the current position to a X,Y point.
void	moveTo (const Point &coord)
	Moves to a specific Point. (But does not draw).
void	moveTo (int x, int y)
	Moves to a X,Y point. (But does not draw).
void	polygon (POINT points[], unsigned count)
	Fills a polygon defined by vertices.
void	polygon (const Point points[], unsigned count)
	Fills a polygon defined by vertices.
void	rectangle (const SmartWin::Rectangle &rect)
	Draws a Rectangle in the Device Context.
void	rectangle (int left, int top, int right, int bottom)
	Draws a Rectangle in the Device Context.
void	selectFont (FontPtr font)
	Selects the given font.
COLORREF	setBkColor (COLORREF crColor)
	Sets the background color for the this Canvas.
bool	setBkMode (bool transparent=false)
	Sets the background mode.
COLORREF	setPixel (int x, int y, COLORREF pixcolor)
	Sets the pixel at (x,y) to be pixcolor. Returns the old pixel color.
unsigned	setTextAlign (unsigned fMode)
	Sets the alignment mode for text operations.
COLORREF	setTextColor (COLORREF crColor)
	Sets the TextColor of the this Canvas.
Protected Member Functions
	Canvas (Widget *widget)
	Not meant for directly instantiation.
	Canvas (HWND hWnd)
	Not meant for directly instantiation.
virtual	~Canvas ()
	Protected Constructor to prevent deletion of class directly.
Protected Attributes
HWND	itsHandle
	Handle to the window of the object.
HDC	itsHdc
	Handle to the Device Context of the object.

---

Detailed Description

Class for painting objects and drawing in a windows.

Helper class containing functions for drawing lines and objects inside a window.
Not meant to be directly instantiated, but rather instantiated through e.g. the PaintCanvas or UpdateCanvas classes.
Related classes

• UpdateCanvas
• PaintCanvas
• FreeCanvas
• Pen

---

Constructor & Destructor Documentation

Canvas

(

HWND

hWnd

)

[explicit, protected]

Not meant for directly instantiation.

Class basically serves as an "abstract" base class for PaintCanvas and UpdateCanvas.
You should not directly instantiate this class but instead use one of the derived classes.

Canvas

(

Widget *

widget

)

[explicit, protected]

Not meant for directly instantiation.

Class basically serves as an "abstract" base class for PaintCanvas and UpdateCanvas.
You should not directly instantiate this class but instead use one of the derived classes.

virtual ~Canvas

(

)

[protected, virtual]

Protected Constructor to prevent deletion of class directly.

Derived class should delete, basically a hack to prevent deletion of a base class pointer

---

Member Function Documentation

int drawText	(	const SmartUtil::tstring &	text,
		const SmartWin::Rectangle &	rect,
		unsigned	format
	)

Draws given string within given Rectangle.

Draw text within a rectangle according to given format.
The format can be any combination of:

• DT_BOTTOM
• DT_CALCRECT
• DT_CENTER
• DT_EDITCONTROL
• DT_END_ELLIPSIS
• DT_EXPANDTABS
• DT_EXTERNALLEADING
• DT_HIDEPREFIX
• DT_INTERNAL
• DT_LEFT
• DT_MODIFYSTRING
• DT_NOCLIP
• DT_NOFULLWIDTHCHARBREAK
• DT_NOPREFIX
• DT_PATH_ELLIPSIS
• DT_PREFIXONLY
• DT_RIGHT
• DT_RTLREADING
• DT_SINGLELINE
• DT_TABSTOP
• DT_TOP
• DT_VCENTER
• DT_WORDBREAK
• DT_WORD_ELLIPSIS

Google for or look at MSDN what their different meaning are.

void ellipse

(

const SmartWin::Rectangle &

rect

)

Draws an ellipse in the Device Context.

Draws an ellipse within the given rectangle.

void ellipse	(	int	left,
		int	top,
		int	right,
		int	bottom
	)

Draws an ellipse in the Device Context.

Draws an ellipse from (left, top) to (right, bottom).

bool extFloodFill	(	int	x,
		int	y,
		COLORREF	color,
		bool	fillTilColorFound
	)

parameter.

If fillTilColorFound is true filling continues outwards from (x,y) until we find the given color and stops there.
If it is false it will fill AS LONG as it finds the given color and stop when it finds another color.
Function returns true if any filling was done, if no filling was done at all it'll return false.

void extTextOut	(	const SmartUtil::tstring &	text,
		unsigned	x,
		unsigned	y
	)

Draws given text inside given Rectangle.

Draw text within coordinates of given Rectangle according to
setTextColor, setTextAlign, SetTextJustification

void fillRectangle	(	const SmartWin::Rectangle &	rect,
		Brush &	brush
	)

Fills a Rectangle in the Device Context with the given brush.

Fills a Rectangle within the given Rectangle.

void fillRectangle	(	int	left,
		int	top,
		int	right,
		int	bottom,
		Brush &	brush
	)

Fills a Rectangle in the Device Context with the given brush.

Fills a Rectangle from (left, top) to (right, bottom).

COLORREF getBkColor

(

)

Gets the background color for the this Canvas.

Gets the background color for extTextOut() calls. Returns the current background color.

HDC getDc

(

)

Returns the Device Context for the Canvas.

Can be used to construct e.g. a Pen object or a HdcModeSetter object

int getDeviceCaps

(

int

nIndex

)

Gets the device capabilities.

HORZRES, VERTRES give pixels

COLORREF getPixel

(

const Point &

coord

)

Returns the pixel's color at given point.

Returns the pixel's color at coord in the Device Context of the object.

COLORREF getPixel	(	int	x,
		int	y
	)

Returns the pixel's color at (x,y).

Returns the pixel's color at (x,y) in the Device Context of the object.

COLORREF getSysColor

(

int

index

)

Gets the color for an system display object.

Example: getSysColor( COLOR_WINDOW )

void line

(

const SmartWin::Rectangle &

rect

)

Draws a line around a Rectangle without filling it.

Draws a line from rect.pos to rect.pos + rect.size
(Use Rectangle if you want to fill it.)

void line	(	const Point &	start,
		const Point &	end
	)

Draws a line from Start to End in the Device Context.

Draws a line from Start to End.
An alternate for line( int xStart, int yStart, int xEnd, int yEnd )

void line	(	int	xStart,
		int	yStart,
		int	xEnd,
		int	yEnd
	)

Draws a line in the Device Context.

Draws a line from (xStart, yStart) to (xEnd, yEnd).

void lineTo

(

const Point &

coord

)

Draws a line from the current position to a specific Point.

Draws to Point in the Device Context of the object. Use line (below) if you know two coordinates.

void lineTo	(	int	x,
		int	y
	)

Draws a line from the current position to a X,Y point.

Draws to x,y in the Device Context of the object. Use line (below) if you know two coordinates.

void moveTo

(

const Point &

coord

)

Moves to a specific Point. (But does not draw).

Moves to Point in the Device Context of the object.

void moveTo	(	int	x,
		int	y
	)

Moves to a X,Y point. (But does not draw).

Moves to x,y in the Device Context of the object.

void polygon	(	POINT	points[],
		unsigned	count
	)

Fills a polygon defined by vertices.

Fills a polygon defined by vertices.

void polygon	(	const Point	points[],
		unsigned	count
	)

Fills a polygon defined by vertices.

Fills a polygon defined by vertices.

void rectangle

(

const SmartWin::Rectangle &

rect

)

Draws a Rectangle in the Device Context.

Draws a Rectangle from (pos) to ( pos + size ). Uses the current Pen to outline, and the current Brush to fill it.

void rectangle	(	int	left,
		int	top,
		int	right,
		int	bottom
	)

Draws a Rectangle in the Device Context.

Draws a Rectangle from (left, top) to (right, bottom). Uses the current Pen to outline, and the current Brush to fill it.

void selectFont

(

FontPtr

font

)

Selects the given font.

Selects the given font for later text operations

COLORREF setBkColor

(

COLORREF

crColor

)

Sets the background color for the this Canvas.

Sets the background color for extTextOut() calls. Returns the previous background color

bool setBkMode

(

bool

transparent = false

)

Sets the background mode.

Can either be transparent (true) or opaque (false). Returns true if the previous background mode was transparent, false if it was opaque

COLORREF setPixel	(	int	x,
		int	y,
		COLORREF	pixcolor
	)

Sets the pixel at (x,y) to be pixcolor. Returns the old pixel color.

Sets the pixel at (x,y) to be pixcol

unsigned setTextAlign

(

unsigned

fMode

)

Sets the alignment mode for text operations.

Returns the previous alignement mode and changes the current mode of text operations. Possible values can be any combination of these:

• TA_CENTER
• TA_LEFT
• TA_RIGHT
• TA_BASELINE
• TA_BOTTOM
• TA_TOP
• TA_NOUPDATECP
• TA_UPDATECP

COLORREF setTextColor

(

COLORREF

crColor

)

Sets the TextColor of the this Canvas.

Sets the TextColor for future TextOut() calls. Returns the previous color.

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Member Data Documentation

HWND itsHandle [protected]

Handle to the window of the object.

Handle of the window that the Canvas is for

HDC itsHdc [protected]

Handle to the Device Context of the object.

Derived classes needs access to this to e.g. call BeginPaint and EndPaint

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