A colormap maps pixel values to RGB color space values.
window specifies the window on whose screen you want to create a
colormap. visual specifies a visual type supported on the screen.
alloc-policy Specifies the colormap entries to be allocated. You
can pass X:Alloc-None or X:Alloc-All.
The X:Create-Colormap function creates and returns a colormap of
the specified visual type for the screen on which window
resides. Note that window is used only to determine the screen.
The initial values of the colormap entries are undefined.
The entries have defined values, but those values are specific to visual and are not defined by X. The alloc-policy must be ‘X:Alloc-None’.
For the other visual classes, if alloc-policy is ‘X:Alloc-None’, the colormap initially has no allocated entries, and clients can allocate them.
If alloc-policy is ‘X:Alloc-All’, the entire colormap is allocated writable. The initial values of all allocated entries are undefined.
The effect is as if an XAllocColorCells call returned all pixel
values from zero to N - 1, where N is the colormap entries value in
visual.
The effect is as if an XAllocColorPlanes call returned a pixel
value of zero and red_mask, green_mask, and blue_mask values containing
the same bits as the corresponding masks in the specified visual.
To create a new colormap when the allocation out of a previously shared colormap has failed because of resource exhaustion, use:
Creates and returns a colormap of the same visual type and for the same screen as the specified colormap. 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 ‘X:Alloc-All’, the new colormap is also created with ‘X:Alloc-All’, 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 ‘X:Alloc-All’, the allocations to be moved are all those pixels and planes that have been allocated by the client and that have not been freed since they were allocated.
A colormap maps pixel values to elements of the RGB datatype. An RGB is a list or vector of 3 integers, describing the red, green, and blue intensities respectively. The integers are in the range 0 - 65535.
The X:Alloc-Color-Cells function allocates read/write color
cells. The number of colors, ncolors must be positive and the
number of planes, nplanes nonnegative. 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^nplanes distinct pixels can
be produced. All of these are allocated writable by the request.
Each mask has exactly one bit set to 1. If contiguous? is non-false and if all masks are ORed together, a single contiguous set of bits set to 1 is formed.
Each mask has exactly three bits set to 1. If contiguous? is non-false and if all masks are ORed together, three contiguous sets of bits set to 1 (one within each pixel subfield) is formed.
The RGB values of the allocated entries are undefined.
X:Alloc-Color-Cells returns a list of two uniform arrays if it
succeeded or #f if it failed. The first array has the pixels allocated
and the second has the plane-masks.
The specified ncolors must be positive; and rgb a list or vector of 3 nonnegative integers. 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 contiguous? is non-false, 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.
Each mask will lie within the corresponding pixel subfield. By ORing together subsets of masks with each pixel value, ncolors * 2(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^nreds independent red entries, ncolors * 2^ngreens independent green entries, and ncolors * 2^nblues independent blue entries.
X:Alloc-Color-Cells returns a list if it succeeded or #f if it
failed. The first element of the list has an array of the pixels
allocated. The second, third, and fourth elements are the red, green,
and blue plane-masks.
Frees the cells represented by pixels whose values are in the
pixels unsigned-integer uniform-vector. 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. Note that freeing an
individual pixel obtained from X:Alloc-Colormap-Cells with a
planes argument may 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.
It is an error 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
‘x:Alloc-All’ to X:Create-Colormap). If more than one pixel
is in error, the one that gets reported is arbitrary.
rgb is a list or vector of 3 integers, describing the red, green, and blue intensities respectively; or an integer ‘#xrrggbb’, packing red, green and blue intensities in the range 0 - 255.
The case-insensitive string color_name specifies the name of a color (for example, red)
X:Colormap-Find-Color allocates a read-only colormap entry
corresponding to the closest RGB value supported by the hardware.
X:Colormap-Find-Color returns the pixel value of the color
closest to the specified RGB or color_name elements
supported by the hardware, if successful; otherwise
X:Colormap-Find-Color returns #f.
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.
Returns a list of 3 integers, describing the red, green, and blue intensities respectively of the colormap entry of the cell indexed by pixel.
The integer pixel must be a valid index into colormap.
rgb is a list or vector of 3 integers, describing the red, green, and blue intensities respectively; or an integer ‘#xrrggbb’, packing red, green and blue intensities in the range 0 - 255.
The case-insensitive string color_name specifies the name of a color (for example, red)
The integer pixel must be a valid index into colormap.
X:Color-Set! changes the colormap entry of the read/write
cell indexed by pixel. If the colormap is an installed map
for its screen, the changes are visible immediately.
Installs the specified colormap for its associated screen. All windows associated with colormap immediately display with true colors. A colormap is associated with a window when the window is created or its attributes changed.
If the specified colormap is not already an installed colormap, the X server generates a ColormapNotify event on each window that has that colormap.
Returns the Color-Conversion-Context of colormap.