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Diffstat (limited to 'console-client/display.h')
| -rw-r--r-- | console-client/display.h | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/console-client/display.h b/console-client/display.h new file mode 100644 index 00000000..44e62773 --- /dev/null +++ b/console-client/display.h @@ -0,0 +1,138 @@ +/* display.h - The interface to and for a display driver. + Copyright (C) 2002 Free Software Foundation, Inc. + Written by Marcus Brinkmann. + + This file is part of the GNU Hurd. + + The GNU Hurd is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + The GNU Hurd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */ + +#ifndef _DISPLAY_H_ +#define _DISPLAY_H_ 1 + +#include <errno.h> +#include <stdint.h> + +#include <hurd/console.h> + + +/* The display drivers are set up by the driver's initialization + routine and added to the console client with driver_add_display. + All subsequent operations on the display are fully synchronized by + the caller. The driver deinitialization routine should call + driver_remove_display. */ + +/* Forward declaration. */ +struct display_ops; +typedef struct display_ops *display_ops_t; + +/* Add the display HANDLE with the operations OPS to the console + client. As soon as this is called, operations on this display may + be performed, even before the function returns. */ +error_t driver_add_display (display_ops_t ops, void *handle); + +/* Remove the display HANDLE with the operations OPS from the console + client. As soon as this function returns, no operations will be + performed on the display anymore. */ +error_t driver_remove_display (display_ops_t ops, void *handle); + + +struct display_ops +{ + /* Set the cursor's position on display HANDLE to column COL and row + ROW. The home position (COL and ROW both being 0) is the upper + left corner of the screen matrix. COL will be smaller than the + width and ROW will be smaller than the height of the display. + + The driver is allowed to delay the effect of this operation until + the UPDATE function is called. */ + error_t (*set_cursor_pos) (void *handle, uint32_t col, uint32_t row); + + + /* Set the cursor's state to STATE on display HANDLE. The possible + values for STATE are defined by the CONS_CURSOR_* symbols in + <hurd/console.h>. + + The driver is allowed to delay the effect of this operation until + the UPDATE function is called. */ + error_t (*set_cursor_status) (void *handle, uint32_t state); + + + /* Scroll the display by DELTA lines up if DELTA is positive, and by + -DELTA lines down if DELTA is negative. DELTA will never be + zero, and the absolute value if DELTA will be smaller than or + equal to the height of the screen matrix. + + The area that becomes free will be filled in a subsequent write + call. The purpose of the function is two-fold: It is called with + an absolute value of DELTA smaller than the screen height to + perform scrolling. It is called with an absolute value of DELTA + equal to the screen height to prepare a full refresh of the + screen. In the latter case the driver should not really perform + any scrolling. Instead it might deallocate limited resources + (like display glyph slots and palette colors) if that helps to + perform the subsequent write. It goes without saying that the + same deallocation, if any, should be performed on the area that + will be filled with the scrolled in content. + + XXX Possibly need a function to invalidate scrollback buffer, or + in general to signal a switch of the console so state can be + reset. Only do this if we make guarantees about validity of + scrollback buffer, of course. + + The driver is allowed to delay the effect of this operation until + the UPDATE function is called. */ + error_t (*scroll) (void *handle, int delta); + + /* Deallocate the scarce resources (like font glyph slots, colors + etc) in the LENGTH entries of the screen matrix starting from + position COL and ROW. This call is immediately followed by calls + to write which cover the same area. If there are no scarce + resources, the caller might do nothing. */ + error_t (*clear) (void *handle, size_t length, uint32_t col, uint32_t row); + + /* Write the text STR with LENGTH characters to column COL and row + ROW on display HANDLE. LENGTH can be longer than the width of + the screen matrix minus COL. In this case the driver should + automatically wrap around the edge. However, LENGTH will never + be so huge that the whole text starting from COL and ROW will go + beyond the lower right corner of the screen matrix. + + The driver is allowed to delay the effect of this operation until + the UPDATE function is called. */ + error_t (*write) (void *handle, conchar_t *str, size_t length, + uint32_t col, uint32_t row); + + /* Flush all the past changes on display HANDLE that have not been + flushed yet. This should make all past changes visible to the + user. The driver is free to make them visible earlier, but it + must happen before returning from this call. + + The purpose of this function is to group several related change + operations together, but also several change operations which + occur in rapid succession. The first grouping is essential to + make it possible for a driver to implement double buffering. The + second grouping is important to keep up performance if there is a + lot of activity on the screen matrix. */ + error_t (*update) (void *handle); + + /* Flash the display HANDLE once. This should be done + immediately. */ + error_t (*flash) (void *handle); + + /* Do not use, do not remove. */ + void (*deprecated) (void *handle, int key); +}; + +#endif /* _DISPLAY_H_ */ |