Applies to: desktop apps only

The SetMapMode function sets the mapping mode of the specified device context. The mapping mode defines the unit of measure used to transform page-space units into device-space units, and also defines the orientation of the device's x and y axes.

Syntax

int SetMapMode(
  __in  HDC hdc,
  __in  int fnMapMode
);

Parameters

hdc [in]

A handle to the device context.

fnMapMode [in]

The new mapping mode. This parameter can be one of the following values.

Value	Meaning
MM_ANISOTROPIC	Logical units are mapped to arbitrary units with arbitrarily scaled axes. Use the SetWindowExtEx and SetViewportExtEx functions to specify the units, orientation, and scaling.
MM_HIENGLISH	Each logical unit is mapped to 0.001 inch. Positive x is to the right; positive y is up.
MM_HIMETRIC	Each logical unit is mapped to 0.01 millimeter. Positive x is to the right; positive y is up.
MM_ISOTROPIC	Logical units are mapped to arbitrary units with equally scaled axes; that is, one unit along the x-axis is equal to one unit along the y-axis. Use the SetWindowExtEx and SetViewportExtEx functions to specify the units and the orientation of the axes. Graphics device interface (GDI) makes adjustments as necessary to ensure the x and y units remain the same size (When the window extent is set, the viewport will be adjusted to keep the units isotropic).
MM_LOENGLISH	Each logical unit is mapped to 0.01 inch. Positive x is to the right; positive y is up.
MM_LOMETRIC	Each logical unit is mapped to 0.1 millimeter. Positive x is to the right; positive y is up.
MM_TEXT	Each logical unit is mapped to one device pixel. Positive x is to the right; positive y is down.
MM_TWIPS	Each logical unit is mapped to one twentieth of a printer's point (1/1440 inch, also called a twip). Positive x is to the right; positive y is up.

 

Return value

If the function succeeds, the return value identifies the previous mapping mode.

If the function fails, the return value is zero.

Remarks

The MM_TEXT mode allows applications to work in device pixels, whose size varies from device to device.

The MM_HIENGLISH, MM_HIMETRIC, MM_LOENGLISH, MM_LOMETRIC, and MM_TWIPS modes are useful for applications drawing in physically meaningful units (such as inches or millimeters).

The MM_ISOTROPIC mode ensures a 1:1 aspect ratio.

The MM_ANISOTROPIC mode allows the x-coordinates and y-coordinates to be adjusted independently.

Examples

For an example, see Using Coordinate Spaces and Transformations.

Requirements

See also

Coordinate Spaces and Transformations Overview

Coordinate Space and Transformation Functions

GetMapMode

SetViewportExtEx

SetViewportOrgEx

SetWindowExtEx

SetWindowOrgEx

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Build date: 3/7/2012