XAllocColor(), XAllocNamedColor(), XAllocColorCells(), XAllocColorPlanes(), XFreeColors() - allocate and free colors
Status XAllocColor (Display *display, Colormap colormap,
XColor *screen_in_out)
Status XAllocNamedColor (Display *display, Colormap colormap,
char *color_name, XColor *screen_def_return,
XColor *exact_def_return)
Status XAllocColorCells (Display *display, Colormap colormap,
Bool contig, unsigned long plane_masks_return[ ],
unsigned int nplanes,
unsigned long pixels_return[ ],
unsigned int npixels)
Status XAllocColorPlanes (Display *display, Colormap colormap,
Bool contig, unsigned long pixels_return[ ],
int ncolors, int nreds, int ngreens,
int nblues, unsigned long *rmask_return,
unsigned long *gmask_return,
unsigned long *bmask_return)
XFreeColors (Display *display, Colormap colormap,
unsigned long pixels[], int npixels,
unsigned long planes)
The XAllocColor(3) function allocates a read-only colormap entry corresponding to the closest RGB value supported by the hardware. XAllocColor(3) returns the pixel value of the color closest to the specified RGB elements supported by the hardware and returns the RGB value actually used. The corresponding colormap cell is read-only. In addition, XAllocColor(3) returns nonzero if it succeeded or zero if it failed. Multiple clients that request the same effective RGB value can be assigned the same read-only entry, thus allowing entries to be shared. When the last client deallocates a shared cell, it is deallocated. XAllocColor(3) does not use or affect the flags in the XColor structure.
XAllocColor(3) can generate a BadColor error.
The XAllocNamedColor(3) function looks up the named color with respect to the screen that is associated with the specified colormap. It returns both the exact database definition and the closest color supported by the screen. The allocated color cell is read-only. The pixel value is returned in screen_def_return. If the color name is not in the Host Portable Character Encoding the result is implementation dependent. Use of uppercase or lowercase does not matter. XLookupColor(3) returns nonzero if a cell is allocated, otherwise it returns zero.
XAllocNamedColor(3) can generate a BadColor error.
delim %% The XAllocColorCells(3) function allocates read/write color cells. The number of colors must be positive and the number of planes nonnegative, or a BadValue error results. If ncolors and nplanes are requested, then ncolors pixels and nplane plane masks are returned. No mask will have any bits set to 1 in common with any other mask or with any of the pixels. By ORing together each pixel with zero or more masks, ncolors * %2 sup nplanes % distinct pixels can be produced. All of these are allocated writable by the request. For GrayScale or PseudoColor, each mask has exactly one bit set to 1. For DirectColor, each has exactly three bits set to 1. If contig is True and if all masks are ORed together, a single contiguous set of bits set to 1 will be formed for GrayScale or PseudoColor and three contiguous sets of bits set to 1 (one within each pixel subfield) for DirectColor. The RGB values of the allocated entries are undefined. XAllocColorCells(3) returns nonzero if it succeeded or zero if it failed.
delim %% The specified ncolors must be positive; and nreds, ngreens, and nblues must be nonnegative, or a BadValue error results. If ncolors colors, nreds reds, ngreens greens, and nblues blues are requested, ncolors pixels are returned; and the masks have nreds, ngreens, and nblues bits set to 1, respectively. If contig is True, each mask will have a contiguous set of bits set to 1. No mask will have any bits set to 1 in common with any other mask or with any of the pixels. For DirectColor, each mask will lie within the corresponding pixel subfield. By ORing together subsets of masks with each pixel value, ncolors * %2 sup (nreds+ngreens+nblues)% distinct pixel values can be produced. All of these are allocated by the request. However, in the colormap, there are only ncolors * %2 sup nreds% independent red entries, ncolors * %2 sup ngreens% independent green entries, and ncolors * %2 sup nblues% independent blue entries. This is true even for PseudoColor. When the colormap entry of a pixel value is changed (using XStoreColors(3), XStoreColor(3), or XStoreNamedColor(3)), the pixel is decomposed according to the masks, and the corresponding independent entries are updated. XAllocColorPlanes(3) returns nonzero if it succeeded or zero if it failed.
The XFreeColors(3) function frees the cells represented by pixels whose values are in the pixels array. The planes argument should not have any bits set to 1 in common with any of the pixels. The set of all pixels is produced by ORing together subsets of the planes argument with the pixels. The request frees all of these pixels that were allocated by the client (using XAllocColor(3), XAllocNamedColor(3), XAllocColorCells(3), and XAllocColorPlanes(3)). Note that freeing an individual pixel obtained from XAllocColorPlanes(3) might not actually allow it to be reused until all of its related pixels are also freed. Similarly, a read-only entry is not actually freed until it has been freed by all clients, and if a client allocates the same read-only entry multiple times, it must free the entry that many times before the entry is actually freed.
All specified pixels that are allocated by the client in the colormap are freed, even if one or more pixels produce an error. If a specified pixel is not a valid index into the colormap, a BadValue error results. If a specified pixel is not allocated by the client (that is, is unallocated or is only allocated by another client), or if the colormap was created with all entries writable (by passing AllocAll to XCreateColormap(3)), a BadAccess error results. If more than one pixel is in error, the one that gets reported is arbitrary.
XAllocColor(3) returns nonzero if it succeeded or zero if it failed.
XLookupColor(3) returns nonzero if a cell is allocated, otherwise it returns zero.
XAllocColorCells(3) returns nonzero if it succeeded or zero if it failed.
XAllocColorPlanes(3) returns nonzero if it succeeded or zero if it failed.
XAllocColorCells(3) can generate BadColor and BadValue errors.
XAllocColorPlanes(3) can generate BadColor and BadValue errors.
XFreeColors(3) can generate BadAccess , BadColor , and BadValue errors.
Xlib