XCreateColormap(3X) XCreateColormap(3X)NAME XCreateColormap, XCopyColormapAndFree, XFreeColormap, XSetWindowColormap - create, copy, and destroy colormaps using the XColor structure SYNOPSIS Colormap XCreateColormap (display, w, visual, alloc) Display *display; Window w; Visual *visual; int alloc; Colormap XCopyColormapAndFree (display, colormap) Display *display; Colormap colormap; XFreeColormap (display, colormap) Display *display; Colormap colormap; XSetWindowColormap (display, w, colormap) Display *display; Window w; Colormap colormap; DESCRIPTION The XCreateColormap function creates a colormap of the specified visual type for the screen on which the specified window resides and associates the Colormap ID with it. Note that the specified window is only used to determine the screen. The initial values of the colormap entries are undefined for the visual classes GrayScale, PseudoColor, and DirectColor. For StaticGray, StaticColor, and TrueColor, the entries have defined values, but those values are specific to the visual and are not defined by X. For StaticGray, StaticColor, and TrueColor, alloc must be AllocNone, or a BadMatch error results. For the other visu- al classes, if alloc is AllocNone, the colormap initially has no allocated entries, and clients can allocate them. For information about the visual types, see Section 3.1 of Xlib - C Language Interface. If alloc is AllocAll, the entire colormap is allocated writ- able. The initial values of all allocated entries are unde- fined. For GrayScale and PseudoColor, the effect is as if an XAllocColorCells call returned all pixel values from 0 to N - 1, where N is the colormap entries value in the specified visual. For DirectColor, the effect is as if an XAllocColorPlanes call returned a pixel value of 0 and November, 1990 1
XCreateColormap(3X) XCreateColormap(3X)red_mask, green_mask, and blue_mask values containing the same bits as the corresponding masks in the specified visu- al. However, in all cases, none of these entries can be freed by using XFreeColors. XCopyColormapAndFree function creates a colormap of the same visual type and for the same screen as the specified color- map and returns the new colormap ID. It also moves all of the client's existing allocation from the specified colormap to the new colormap with their color values intact and their read-only or writable characteristics intact and frees those entries in the specified colormap. Color values in other entries in the new colormap are undefined. If the specified colormap was created by the client with alloc set to Allo- cAll, the new colormap is also created with AllocAll, all color values for all entries are copied from the specified colormap, and then all entries in the specified colormap are freed. If the specified colormap was not created by the client with AllocAll, the allocations to be moved are all those pixels and planes that have been allocated by the client using XAllocColor, XAllocNamedColor, XAllocColorCells, or XAllocColorPlanes and that have not been freed since they were allocated. The XFreeColormap function deletes the association between the colormap resource ID and the colormap and frees the colormap storage. However, this function has no effect on the default colormap for a screen. If the specified color- map is an installed map for a screen, it is uninstalled (see XUninstallColormap). If the specified colormap is defined as the colormap for a window (by XCreateWindow, XSetWin- dowColormap, or XChangeWindowAttributes), XFreeColormap changes the colormap associated with the window to None and generates a ColormapNotify event. X does not define the colors displayed for a window with a colormap of None. The XSetWindowColormap function sets the specified colormap of the specified window. The colormap must have the same visual type as the window, or a BadMatch error results. Arguments These functions accept the following arguments: alloc Specifies the colormap entries to be allocated. One of the following constants can be passed: AllocNone or AllocAll. colormap Specifies the colormap ID. display Specifies the connection to the X server. 2 November, 1990
XCreateColormap(3X) XCreateColormap(3X)visual Specifies a pointer to a visual type supported on the screen. If the visual type is not one supported by the screen, the function returns a BadMatch er- ror. w Specifies the window ID. Structures The XColor structure is defined as follows. typedef struct { unsigned long pixel; /* pixel value */ unsigned short red, green, blue;/* rgb values */ char flags; /* DoRed, DoGreen, */ /* DoBlue */ char pad; } XColor; The red, green, and blue members are scaled between 0 and 65535. On full in a color is a value of 65535 independent of the number of bits actually used in the display hardware. Half brightness in a color is a value of 32767, and off is 0. This representation gives uniform results for color values across different screens. In some functions, the flags member controls which of the red, green, and blue members is used and can be one or more of DoRed, DoGreen, and DoBlue. ERRORS BadAlloc The server failed to allocate the requested resource or server memory. BadColor A value for a Colormap argument does not name a de- fined colormap. November, 1990 3
XCreateColormap(3X) XCreateColormap(3X)BadMatch An InputOnly window is used as a drawable; or, an argument or pair of arguments has the correct type and range but fails to match in some other required way. BadValue A numeric value falls outside the range of values accepted by the request. Unless a range is speci- fied for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error. BadWindow A value for a Window argument does not name a de- fined window. XCreateColormap can generate BadAlloc, BadMatch, BadValue, and BadWindow errors. XCopyColormapAndFree can generate BadAlloc and BadColor errors. XFreeColormap can generate a BadColor error. XSetWindowColormap can generate BadColor, BadMatch, and BadWindow errors. SEE ALSO XAllocColor(3X), XChangeWindowAttributes(3X), XCreateWindow(3X), XQueryColor(3X), XStoreColors(3X)Xlib - C Language Interface4 November, 1990