Native Window Driver (cdnative.h)

This driver provides access to an existing Native Window, a basic element of the user-interface system.

Use

The canvas is created by means of a call to the function cdCreateCanvas(CD_NATIVEWINDOW, Data), after which other functions in the CD library can be called as usual. This function creates a CD canvas based on an existing system canvas. The parameter Data is a pointer to a handle of the canvas. It is system-dependent, having a different meaning in each platform:

Microsoft Windows: can be the handle of the Windows window (HWND) or the handle of a previously created Device Context (HDC), or can be a string in the format "hdc width height" or, in C, "%p %d %d".
X-Windows: "display window" or, in C, "%p %lu" (uses the default screen).

The string has the same format as the IUP attribute CONID, so it is possible to create a canvas using this driver, but based on a IUP canvas. Therefore, it is no longer necessary to use the IUP driver. For instance:

cdCreateCanvas(CD_NATIVEWINDOW, IupGetAttribute(myIupCanvas, "CONID")).
IupSetAttribute(myIupCanvas, "_CD_CANVAS", myCdCanvas);

Any amount of such canvases may exist simultaneously, but they should not use the same window. It is important to note that a call to function cdKillCanvas is required to close the file properly.

In CDLUA, the creation parameter must be a string in X-Windows and a userdata in Microsoft Windows.

Exclusive Functions

void cdGetScreenSize(int *width, int *height, double *width_mm, double *height_mm); [in C]
cdGetScreenSize() -> (width, heigth, mm_width, mm_height: number) [in Lua]

Equivalent to function cdGetCanvasSize, but returns the values relative to the main screen of the window system.

int cdGetScreenColorPlanes(void); [in C]
cdGetScreenColorPlanes() -> (bpp: number) [in Lua]

Equivalent to function cdGetColorPlanes, but returns the value relative to the main screen of the window system.

Behavior of Functions

This driver is greatly platform-dependent. For further detail, see the Behavior of Functions in each platform: Macintosh (QuickDraw), Microsoft Windows (GDI), Windows Using GDI+, X-Windows (XLIB). However, it should be noted that some functions behave differently from the basic functions of each platform.

Control

• cdActivate: updates the canvas size; it might have been resized.