Mapping Operations
[GDI functions]

Defines

• #define GetMapMode(hdc)   (int)GetDCAttr (hdc, DC_ATTR_MAP_MODE)

  Retrives the current mapping mode of a DC.
  

• #define SetMapMode(hdc, mapmode)   (int)SetDCAttr (hdc, DC_ATTR_MAP_MODE, (DWORD)mapmode)

  Sets the mapping mode of a display context.
  

• #define GetViewportOrg(hdc, pPt)   GetDCLCS(hdc, DC_LCS_VORG, pPt)

  Retrieves the x-coordinates and y-coordinates of the viewport origin for a device context.
  

• #define GetViewportExt(hdc, pPt)   GetDCLCS(hdc, DC_LCS_VEXT, pPt)

  Retrieves the x-extents and y-extents of the current viewport for a device context.
  

• #define GetWindowOrg(hdc, pPt)   GetDCLCS(hdc, DC_LCS_WORG, pPt)

  Retrieves the x-coordinates and y-coordinates of the window for a device context.
  

• #define GetWindowExt(hdc, pPt)   GetDCLCS(hdc, DC_LCS_WEXT, pPt)

  Retrieves the x-extents and y-extents of the current window for a device context.
  

• #define SetViewportOrg(hdc, pPt)   SetDCLCS(hdc, DC_LCS_VORG, pPt)

  Sets the x-coordinates and y-coordinates of the viewport origin for a device context.
  

• #define SetViewportExt(hdc, pPt)   SetDCLCS(hdc, DC_LCS_VEXT, pPt)

  Sets the x-extents and y-extents of the current viewport for a device context.
  

• #define SetWindowOrg(hdc, pPt)   SetDCLCS(hdc, DC_LCS_WORG, pPt)

  Sets the x-coordinates and y-coordinates of the window for a device context.
  

• #define SetWindowExt(hdc, pPt)   SetDCLCS(hdc, DC_LCS_WEXT, pPt)

  Sets the x-extents and y-extents of the current window for a device context.
  

Functions

• MG_EXPORT void GUIAPI GetDCLCS (HDC hdc, int which, POINT *pt)

  Retrives mapping parameters of a device context.
  

• MG_EXPORT void GUIAPI SetDCLCS (HDC hdc, int which, const POINT *pt)

  Sets mapping parameters of a device context.
  

• MG_EXPORT void GUIAPI DPtoLP (HDC hdc, POINT *pPt)

  Converts device coordinates into logical coordinates.
  

• MG_EXPORT void GUIAPI LPtoDP (HDC hdc, POINT *pPt)

  Converts logical coordinates into device coordinates.
  

---

Detailed Description

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.

So far, MiniGUI support only two mapping mode:

• MM_TEXT
  Each logical unit is mapped to on device pixel. Positive x is to the right; positive y is down.
• MM_ANISOTROPIC
  Logical units are mapped to arbitrary units with arbitrarily scaled axes; Use SetWindowExt and SetViewportExt functions to specify the units, orientation, and scaling required.

The following formula shows the math involved in converting a point from page space to device space:

      Dx = ((Lx - WOx) * VEx / WEx) + VOx

The following variables are involved:

• Dx x value in device units
• Lx x value in logical units (also known as page space units)
• WO window x origin
• VO viewport x origin
• WE window x-extent
• VE viewport x-extent

The same equation with y replacing x transforms the y component of a point. The formula first offsets the point from its coordinate origin. This value, no longer biased by the origin, is then scaled into the destination coordinate system by the ratio of the extents. Finally, the scaled value is offset by the destination origin to its final mapping.

---

Define Documentation

#define GetMapMode (  hdc   )     (int)GetDCAttr (hdc, DC_ATTR_MAP_MODE)

Retrives the current mapping mode of a DC. This function retrives the current mapping mode of the DC hdc. So far, MiniGUI support two mapping modes: MM_TEXT and MM_ANISOTROPIC. Parameters: hdc  The device context. Returns: The current mapping mode, can be either MM_TEXT or MM_ANISOTROPIC. Note: Defined as a macro calling GetDCAttr for _USE_NEWGAL. If _USE_NEWGAL is not defined, GetMapMode is defined as a function, and have the same semantics as this macro. See also: SetWindowExt, SetViewportExt, SetMapMode Definition at line 3839 of file gdi.h.

#define GetViewportExt (  hdc, pPt   )     GetDCLCS(hdc, DC_LCS_VEXT, pPt)

Retrieves the x-extents and y-extents of the current viewport for a device context. This function retrives the x-extents and y-extens of the current viewport of the specified device context hdc. Parameters: hdc  The device context. pPt  The viewport extents will be returned through this buffer. Note: Defined as a macro calling GetDCLCS for _USE_NEWGAL. If _USE_NEWGAL is not defined, GetViewportExt is defined as a function, and have the same semantics as this macro. See also: GetMapMode, SetViewportExt Definition at line 3970 of file gdi.h.

#define GetViewportOrg (  hdc, pPt   )     GetDCLCS(hdc, DC_LCS_VORG, pPt)

Retrieves the x-coordinates and y-coordinates of the viewport origin for a device context. This function retrives the x-coordinates and y-coordinates of the viewport origin of the specified device context hdc. Parameters: hdc  The device context. pPt  The viewport origin will be returned through this buffer. Note: Defined as a macro calling GetDCLCS for _USE_NEWGAL. If _USE_NEWGAL is not defined, GetViewportOrg is defined as a function, and have the same semantics as this macro. See also: GetMapMode, SetViewportOrg Definition at line 3951 of file gdi.h.

#define GetWindowExt (  hdc, pPt   )     GetDCLCS(hdc, DC_LCS_WEXT, pPt)

Retrieves the x-extents and y-extents of the current window for a device context. This function retrives the x-extents and y-extens of the current window of the specified device context hdc. Parameters: hdc  The device context. pPt  The window extents will be returned through this buffer. Note: Defined as a macro calling GetDCLCS for _USE_NEWGAL. If _USE_NEWGAL is not defined, GetWindowExt is defined as a function, and have the same semantics as this macro. See also: GetMapMode, SetWindowExt Definition at line 4008 of file gdi.h.

#define GetWindowOrg (  hdc, pPt   )     GetDCLCS(hdc, DC_LCS_WORG, pPt)

Retrieves the x-coordinates and y-coordinates of the window for a device context. This function retrives the x-coordinates and y-coordinates of the window origin of the specified device context hdc. Parameters: hdc  The device context. pPt  The window origin will be returned through this buffer. Note: Defined as a macro calling GetDCLCS for _USE_NEWGAL. If _USE_NEWGAL is not defined, GetWindowOrg is defined as a function, and have the same semantics as this macro. See also: GetMapMode, SetWindowOrg Definition at line 3989 of file gdi.h.

#define SetMapMode (  hdc, mapmode   )     (int)SetDCAttr (hdc, DC_ATTR_MAP_MODE, (DWORD)mapmode)

Sets the mapping mode of a display context. This function sets the mapping mode of the specified display context hdc. So far, MiniGUI support two mapping modes: MM_TEXT and MM_ANISOTROPIC. Parameters: hdc  The device context. mapmode  The new mapping mode, should be either MM_TEXT or MM_ANISOTROPIC. Returns: The old mapping mode, either MM_TEXT or MM_ANISOTROPIC. Note: Defined as a macro calling SetDCAttr for _USE_NEWGAL. If _USE_NEWGAL is not defined, SetMapMode is defined as a function, and have the same semantics as this macro. See also: SetWindowExt, SetViewportExt, SetMapMode Definition at line 3860 of file gdi.h.

#define SetViewportExt (  hdc, pPt   )     SetDCLCS(hdc, DC_LCS_VEXT, pPt)

Sets the x-extents and y-extents of the current viewport for a device context. This function sets the x-extents and y-extens of the current viewport of the specified device context hdc. Parameters: hdc  The device context. pPt  The viewport extents will be set. Note: Defined as a macro calling GetDCLCS for _USE_NEWGAL. If _USE_NEWGAL is not defined, SetViewportExt is defined as a function, and have the same semantics as this macro. See also: GetMapMode, GetViewportExt Definition at line 4046 of file gdi.h.

#define SetViewportOrg (  hdc, pPt   )     SetDCLCS(hdc, DC_LCS_VORG, pPt)

Sets the x-coordinates and y-coordinates of the viewport origin for a device context. This function sets the x-coordinates and y-coordinates of the viewport origin of the specified device context hdc. Parameters: hdc  The device context. pPt  The viewport origin will be set. Note: Defined as a macro calling GetDCLCS for _USE_NEWGAL. If _USE_NEWGAL is not defined, SetViewportOrg is defined as a function, and have the same semantics as this macro. See also: GetMapMode, GetViewportOrg Definition at line 4027 of file gdi.h.

#define SetWindowExt (  hdc, pPt   )     SetDCLCS(hdc, DC_LCS_WEXT, pPt)

Sets the x-extents and y-extents of the current window for a device context. This function sets the x-extents and y-extens of the current window of the specified device context hdc. Parameters: hdc  The device context. pPt  The window extents will be set. Note: Defined as a macro calling GetDCLCS for _USE_NEWGAL. If _USE_NEWGAL is not defined, SetWindowExt is defined as a function, and have the same semantics as this macro. See also: GetMapMode, GetWindowExt Definition at line 4084 of file gdi.h.

#define SetWindowOrg (  hdc, pPt   )     SetDCLCS(hdc, DC_LCS_WORG, pPt)

Sets the x-coordinates and y-coordinates of the window for a device context. This function sets the x-coordinates and y-coordinates of the window origin of the specified device context hdc. Parameters: hdc  The device context. pPt  The window origin will be set. Note: Defined as a macro calling GetDCLCS for _USE_NEWGAL. If _USE_NEWGAL is not defined, SetWindowOrg is defined as a function, and have the same semantics as this macro. See also: GetMapMode, GetWindowOrg Definition at line 4065 of file gdi.h.

---

Function Documentation

void GUIAPI DPtoLP (  HDC  hdc, POINT *  pPt )

Converts device coordinates into logical coordinates. This function converts device coordinates into logical coordinates in the device context hdc. The conversion depends on the mapping mode of the display context, the settings of the origins and extents for the window and viewport. The x-coordinate and y-coordinate contained in struct pPt will be transformed. Parameters: hdc  The device context. pPt  The coordinates to be converted, and the transformed coordinates will be contained in this buffer after the function returns. See also: LPtoDP

void GUIAPI GetDCLCS (  HDC  hdc, int  which, POINT *  pt )

Retrives mapping parameters of a device context. This function retrives mapping paramters of the specified device context hdc when the mapping mode is not MM_TEXT. Parameters: hdc  The device context. which  Which parameter you want to retrive, can be one of the following values: DC_LCS_VORG Retrives the x-coordinates and y-coordinates of the viewport origin. DC_LCS_VEXT Retrives the x-extents and y-extents of the current viewport. DC_LCS_WORG Retrives the x-coordinates and y-coordinates of the window origin. DC_LCS_WEXT Retrives the x-extents and y-extents of the window. Parameters: pt  The coordinates or extents will be returned through this buffer. Note: Only defined for _USE_NEWGAL See also: GetMapMode, SetMapMode, SetDCLCS

void GUIAPI LPtoDP (  HDC  hdc, POINT *  pPt )

Converts logical coordinates into device coordinates. This function converts logical coordinates into device coordinates in the device context hdc. The conversion depends on the mapping mode of the display context, the settings of the origins and extents for the window and viewport. The x-coordinate and y-coordinate contained in struct pPt will be transformed. Parameters: hdc  The device context. pPt  The coordinates to be converted, and the transformed coordinates will be contained in this buffer after the function returns. See also: DPtoLP

void GUIAPI SetDCLCS (  HDC  hdc, int  which, const POINT *  pt )

Sets mapping parameters of a device context. This function sets mapping paramters of the specified device context hdc when the mapping mode is not MM_TEXT. Parameters: hdc  The device context. which  Which parameter you want to retrive, can be one of the following values: DC_LCS_VORG Sets the x-coordinates and y-coordinates of the viewport origin. DC_LCS_VEXT Sets the x-extents and y-extents of the current viewport. DC_LCS_WORG Sets the x-coordinates and y-coordinates of the window origin. DC_LCS_WEXT Sets the x-extents and y-extents of the window. Parameters: pt  The coordinates or extents will be set. Note: Only defined for _USE_NEWGAL See also: GetMapMode, SetMapMode, GetDCLCS

---