Graphics Device Interface (GDI)

Detailed Description

The following are functions and macros related to GDI (Graphics Device Interface) access.

Related Overviews: Device Contexts

Related class group: Graphics Device Interface (GDI)

Macros
#define	wxDROP_ICON(name)
	This macro creates either a cursor (MSW) or an icon (elsewhere) with the given name (of type const char*). More...
#define	wxBITMAP(bitmapName)
	This macro loads a bitmap from either application resources (on the platforms for which they exist, i.e. Windows) or from an XPM file. More...
#define	wxBITMAP_PNG(bitmapName)
	Creates a bitmap from either application resources or embedded image data in PNG format. More...
#define	wxBITMAP_PNG_FROM_DATA(bitmapName)
	Creates a bitmap from embedded image data in PNG format. More...
#define	wxICON(iconName)
	This macro loads an icon from either application resources (on the platforms for which they exist, i.e. Windows) or from an XPM file. More...

Functions
bool	wxIsDragResultOk (wxDragResult res)
	Returns true if res indicates that something was done during a DnD operation, i.e. More...
bool	wxColourDisplay ()
	Returns true if the display is colour, false otherwise. More...
int	wxDisplayDepth ()
	Returns the depth of the display (a value of 1 denotes a monochrome display). More...
void	wxSetCursor (const wxCursor &cursor)
	Globally sets the cursor; only has an effect on Windows, Mac and GTK+. More...
void	wxClientDisplayRect (int *x, int *y, int *width, int *height)
	Returns the dimensions of the work area on the display. More...
wxRect	wxGetClientDisplayRect ()
	Returns the dimensions of the work area on the display. More...
wxSize	wxGetDisplayPPI ()
	Returns the display resolution in pixels per inch. More...
void	wxDisplaySize (int *width, int *height)
	Returns the display size in pixels. More...
wxSize	wxGetDisplaySize ()
	Returns the display size in pixels. More...
void	wxDisplaySizeMM (int *width, int *height)
	Returns the display size in millimeters. More...
wxSize	wxGetDisplaySizeMM ()
	Returns the display size in millimeters. More...
bool	wxMakeMetafilePlaceable (const wxString &filename, int minX, int minY, int maxX, int maxY, float scale=1.0)
	Given a filename for an existing, valid metafile (as constructed using wxMetafileDC) makes it into a placeable metafile by prepending a header containing the given bounding box. More...

Macro Definition Documentation

wxBITMAP

#define wxBITMAP

(

bitmapName

)

This macro loads a bitmap from either application resources (on the platforms for which they exist, i.e. Windows) or from an XPM file.

You can use wxHAS_IMAGES_IN_RESOURCES to check if the XPM needs to be included when using this macro.

See also wxBITMAP_PNG() if you want to use images with alpha channel.

See also

Including Bitmaps in Your Program, wxICON()

Include file:

#include <wx/gdicmn.h> 

wxBITMAP_PNG

#define wxBITMAP_PNG

(

bitmapName

)

Creates a bitmap from either application resources or embedded image data in PNG format.

This macro is similar to wxBITMAP() but works with bitmap data in PNG format and not BMP or XPM.

Under Windows the given bitmapName must be present in the application resource file with the type RCDATA and refer to a PNG image. I.e. you should have a definition similar to the following in your .rc file:

mybitmap    RCDATA  "mybitmap.png"

to be able to use wxBITMAP_PNG(mybitmap) in the code.

Under macOS the file with the specified name and "png" extension must be present in the "Resources" subdirectory of the application bundle.

Under the other platforms, this is equivalent to wxBITMAP_PNG_FROM_DATA() and so loads the image data from the array called bitmapName_png that must exist. Notice that it must be an array and not a pointer as the macro needs to be able to determine its size. Such an array can be produced by a number of conversion programs. A very simple one is included in wxWidgets distribution as misc/scripts/png2c.py.

Finally notice that you must register PNG image handler to be able to load bitmaps from PNG data. This can be done either by calling wxInitAllImageHandlers() which also registers all the other image formats or including the necessary header:

#include <wx/imagpng.h>

and calling

wxImage::AddHandler(new wxPNGHandler);

in your application startup code.

See also

Including Bitmaps in Your Program, wxBITMAP_PNG_FROM_DATA()

Include file:

#include <wx/gdicmn.h> 

Since

2.9.5

wxBITMAP_PNG_FROM_DATA

#define wxBITMAP_PNG_FROM_DATA

(

bitmapName

)

Creates a bitmap from embedded image data in PNG format.

This macro is a thin wrapper around wxBitmap::NewFromPNGData() and takes just the base name of the array containing the image data and computes its size internally. In other words, the array called bitmapName_png must exist. Notice that it must be an array and not a pointer as the macro needs to be able to determine its size. Such an array can be produced by a number of conversion programs. A very simple one is included in wxWidgets distribution as misc/scripts/png2c.py.

You can use wxBITMAP_PNG() to load the PNG bitmaps from resources on the platforms that support this and only fall back to loading them from data under the other ones (i.e. not Windows and not macOS).

Include file:

#include <wx/gdicmn.h> 

Since

2.9.5

wxDROP_ICON

#define wxDROP_ICON

(

name

)

This macro creates either a cursor (MSW) or an icon (elsewhere) with the given name (of type const char*).

Under MSW, the cursor is loaded from the resource file and the icon is loaded from XPM file under other platforms.

This macro should be used with wxDropSource::wxDropSource().

Returns

wxCursor on MSW, otherwise returns a wxIcon

Include file:

#include <wx/dnd.h> 

wxICON

#define wxICON

(

iconName

)

This macro loads an icon from either application resources (on the platforms for which they exist, i.e. Windows) or from an XPM file.

You can use wxHAS_IMAGES_IN_RESOURCES to check if the XPM needs to be included when using this macro.

See also wxBITMAP_PNG() if you want to use images with alpha channel.

See also

Including Bitmaps in Your Program, wxBITMAP()

Include file:

#include <wx/gdicmn.h> 

Function Documentation

wxClientDisplayRect()

void wxClientDisplayRect	(	int *	x,
		int *	y,
		int *	width,
		int *	height
	)

Returns the dimensions of the work area on the display.

This is the same as wxGetClientDisplayRect() but allows retrieving the individual components instead of the entire rectangle.

Any of the output pointers can be nullptr if the corresponding value is not needed by the caller.

See also

wxDisplay

Include file:

#include <wx/gdicmn.h> 

wxColourDisplay()

bool wxColourDisplay

(

)

Returns true if the display is colour, false otherwise.

Note

Use of this function is not recommended in the new code as it only works for the primary display. Use wxDisplay::GetDepth() to retrieve the depth of the appropriate display and compare it with 1 instead.

Include file:

#include <wx/gdicmn.h> 

wxDisplayDepth()

int wxDisplayDepth

(

)

Returns the depth of the display (a value of 1 denotes a monochrome display).

Note

Use of this function is not recommended in the new code as it only works for the primary display. Use wxDisplay::GetDepth() to retrieve the depth of the appropriate display instead.

Include file:

#include <wx/gdicmn.h> 

wxDisplaySize()

void wxDisplaySize	(	int *	width,
		int *	height
	)

Returns the display size in pixels.

Note

Use of this function is not recommended in the new code as it only works for the primary display. Use wxDisplay::GetGeometry() to retrieve the size of the appropriate display instead.

Either of output pointers can be nullptr if the caller is not interested in the corresponding value.

See also

wxGetDisplaySize(), wxDisplay

Include file:

#include <wx/gdicmn.h> 

wxDisplaySizeMM()

void wxDisplaySizeMM	(	int *	width,
		int *	height
	)

Returns the display size in millimeters.

Either of output pointers can be nullptr if the caller is not interested in the corresponding value.

See also

wxGetDisplaySizeMM(), wxDisplay

Include file:

#include <wx/gdicmn.h> 

wxGetClientDisplayRect()

wxRect wxGetClientDisplayRect

(

)

Returns the dimensions of the work area on the display.

On Windows this means the area not covered by the taskbar, etc. Other platforms are currently defaulting to the whole display until a way is found to provide this info for all window managers, etc.

See also

wxDisplay

Include file:

#include <wx/gdicmn.h> 

wxGetDisplayPPI()

wxSize wxGetDisplayPPI

(

)

Returns the display resolution in pixels per inch.

The x component of the returned wxSize object contains the horizontal resolution and the y one – the vertical resolution.

Note

Use of this function is not recommended in the new code as it only works for the primary display. Use wxDisplay::GetPPI() to retrieve the resolution of the appropriate display instead.

Include file:

#include <wx/gdicmn.h> 

See also

wxDisplay

Since

2.9.0

wxGetDisplaySize()

wxSize wxGetDisplaySize

(

)

Returns the display size in pixels.

Note

Use of this function is not recommended in the new code as it only works for the primary display. Use wxDisplay::GetGeometry() to retrieve the size of the appropriate display instead.

See also

wxDisplay

Include file:

#include <wx/gdicmn.h> 

wxGetDisplaySizeMM()

wxSize wxGetDisplaySizeMM

(

)

Returns the display size in millimeters.

See also

wxDisplay

Include file:

#include <wx/gdicmn.h> 

wxIsDragResultOk()

bool wxIsDragResultOk

(

wxDragResult

res

)

Returns true if res indicates that something was done during a DnD operation, i.e.

is neither error nor none nor cancel.

wxMakeMetafilePlaceable()

bool wxMakeMetafilePlaceable	(	const wxString &	filename,
		int	minX,
		int	minY,
		int	maxX,
		int	maxY,
		float	scale = 1.0
	)

Given a filename for an existing, valid metafile (as constructed using wxMetafileDC) makes it into a placeable metafile by prepending a header containing the given bounding box.

The bounding box may be obtained from a device context after drawing into it, using the functions wxDC::MinX(), wxDC::MinY(), wxDC::MaxX() and wxDC::MaxY().

In addition to adding the placeable metafile header, this function adds the equivalent of the following code to the start of the metafile data:

SetMapMode(dc, MM_ANISOTROPIC);
SetWindowOrg(dc, minX, minY);
SetWindowExt(dc, maxX - minX, maxY - minY);

This simulates the wxMM_TEXT mapping mode, which wxWidgets assumes.

Placeable metafiles may be imported by many Windows applications, and can be used in RTF (Rich Text Format) files.

scale allows the specification of scale for the metafile.

This function is only available under Windows.

Include file:

#include <wx/metafile.h> 

wxSetCursor()

void wxSetCursor

(

const wxCursor &

cursor

)

Globally sets the cursor; only has an effect on Windows, Mac and GTK+.

You should call this function with wxNullCursor to restore the system cursor.

See also

wxCursor, wxWindow::SetCursor()

Include file:

#include <wx/gdicmn.h>