The initial values of the colormap entries are undefined for the visual classes _G_r_a_y_S_c_a_l_e, _P_s_e_u_d_o_C_o_l_o_r, and _D_i_r_e_c_t_C_o_l_o_r. For _S_t_a_t_i_c_G_r_a_y, _S_t_a_t_i_c_C_o_l_o_r, and _T_r_u_e_C_o_l_o_r, the entries have defined values, but those values are specific to the visual and are not defined by X. For _S_t_a_t_i_c_G_r_a_y, _S_t_a_t_i_c_C_o_l_o_r, and _T_r_u_e_C_o_l_o_r, alloc must be _A_l_l_o_c_N_o_n_e, or a _B_a_d_M_a_t_c_h error results. For the other visual classes, if alloc is _A_l_l_o_c_N_o_n_e, the colormap initially has no allocated entries, and clients can allocate them. For information about the visual types, see section 3.1.
If alloc is _A_l_l_o_c_A_l_l, the entire colormap is allocated writable. The initial values of all allocated entries are undefined. For _G_r_a_y_S_c_a_l_e and _P_s_e_u_d_o_C_o_l_o_r, the effect is as if an _X_A_l_l_o_c_C_o_l_o_r_C_e_l_l_s call returned all pixel values from zero to N - 1, where N is the colormap entries value in the specified visual. For _D_i_r_e_c_t_C_o_l_o_r, the effect is as if an _X_A_l_l_o_c_C_o_l_o_r_P_l_a_n_e_s 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. However, in all cases, none of these entries can be freed by using _X_F_r_e_e_C_o_l_o_r_s.
_X_C_r_e_a_t_e_C_o_l_o_r_m_a_p can generate _B_a_d_A_l_l_o_c, _B_a_d_M_a_t_c_h, _B_a_d_V_a_l_u_e, and _B_a_d_W_i_n_d_o_w errors.
The _X_C_o_p_y_C_o_l_o_r_m_a_p_A_n_d_F_r_e_e function creates a colormap of the same visual type and for the same screen as the specified colormap 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 _A_l_l_o_c_A_l_l, the new colormap is also created with _A_l_l_o_c_A_l_l, 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 _A_l_l_o_c_A_l_l, the allocations to be moved are all those pixels and planes that have been allocated by the client using _X_A_l_l_o_c_C_o_l_o_r, _X_A_l_l_o_c_N_a_m_e_d_C_o_l_o_r, _X_A_l_l_o_c_C_o_l_o_r_C_e_l_l_s, or _X_A_l_l_o_c_C_o_l_o_r_P_l_a_n_e_s and that have not been freed since they were allocated.
_X_C_o_p_y_C_o_l_o_r_m_a_p_A_n_d_F_r_e_e can generate _B_a_d_A_l_l_o_c and _B_a_d_C_o_l_o_r errors.
The _X_F_r_e_e_C_o_l_o_r_m_a_p 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 colormap is an installed map for a screen, it is uninstalled (see _X_U_n_i_n_s_t_a_l_l_C_o_l_o_r_m_a_p). If the specified colormap is defined as the colormap for a window (by _X_C_r_e_a_t_e_W_i_n_d_o_w, _X_S_e_t_W_i_n_d_o_w_C_o_l_o_r_m_a_p, or _X_C_h_a_n_g_e_W_i_n_d_o_w_A_t_t_r_i_b_u_t_e_s), _X_F_r_e_e_C_o_l_o_r_m_a_p changes the colormap associated with the window to _N_o_n_e and generates a _C_o_l_o_r_m_a_p_N_o_t_i_f_y event. X does not define the colors displayed for a window with a colormap of _N_o_n_e.
_X_F_r_e_e_C_o_l_o_r_m_a_p can generate a _B_a_d_C_o_l_o_r error.
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 values are always in the range 0 to 65535 inclusive, independent of the number of bits actually used in the display hardware. The server scales these values down to the range used by the hardware. Black is represented by (0,0,0), and white is represented by (65535,65535,65535). In some functions, the flags member controls which of the red, green, and blue members is used and can be the inclusive OR of zero or more of _D_o_R_e_d, _D_o_G_r_e_e_n, and _D_o_B_l_u_e.