SetGraphicsMode

SetGraphicsMode

The SetGraphicsMode function sets the graphics mode for the specified device context.

int SetGraphicsMode(

HDC hdc,	// handle of the device context
int iMode	// graphics mode
);

Parameters

hdc

Identifies the device context.

iMode

Specifies the graphics mode. This parameter can be one of the following values:

Value	Meaning
GM_COMPATIBLE	Sets the graphics mode that is compatible with Windows version 3.1. This is the default mode. If this value is specified, the application can only modify the world-to-device transform by calling functions that set window and viewport extents and origins, but not by using SetWorldTransform or ModifyWorldTransform; calls to those functions will fail. Examples of functions that set window and viewport extents and origins are SetViewportExtEx and SetWindowExtEx.
GM_ADVANCED	Windows NT: Sets the advanced graphics mode that allows world transformations. This value must be specified if the application will set or modify the world transformation for the specified device context. In this mode all graphics, including text output, fully comforms to the world-to-device transformation specified in the device context. Windows 95: The GM_ADVANCED value is not supported. When playing enhanced metafiles, Windows 95 does its best to ensure that enhanced metafiles on Windows 95 look the same as they do on Windows NT. To accomplish this, Windows 95 may simulate GM_ADVANCED mode when playing specific enhanced metafile records.

Return Values

If the function succeeds, the return value is the old graphics mode.

If the function fails, the return value is zero.

Remarks

There are three areas in which graphics output differs according to the graphics mode:

1.Text Output: In the GM_COMPATIBLE mode, TrueType (or vector font) text output behaves much the same way as raster font text output with respect to the world-to-device transform in the DC. The TrueType text is always written from left to right and right side up, even if the rest of the graphics will be flipped in the x or y axis. Only the height of the TrueType (or vector font) text is scaled appropriately. The only way to write nonhorizontal text in the GM_COMPATIBLE mode is to specify nonzero escapement and orientation for the logical font selected in this device context.

In the GM_ADVANCED mode, TrueType (or vector font) text output fully conforms to the world-to-device transform in the device context. The raster fonts only have very limited transformation capabilities (stretching by some integer factors). Graphics device interface (GDI) tries to produce the best output it can with raster fonts for non-trivial transforms.

2.Rectangle Exclusion: If the default GM_COMPATIBLE graphics mode is set, the system excludes bottom and rightmost edges when it draws rectangles.

The GM_ADVANCED graphics mode is required if applications want to draw rectangles that are bottom-right inclusive.

3.Arc Drawing: If the default GM_COMPATIBLE graphics mode is set, GDI draws arcs using the current arc direction in the device space. With this convention, arcs do not respect page-to-device transforms that require a flip along the x or y axis.

If the GM_ADVANCED graphics mode is set, GDI always draws arcs in the counterclockwise direction in logical space. This is equivalent to the statement that, in the GM_ADVANCED graphics mode, both arc control points and arcs themselves fully respect the device context's world-to-device transform.