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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Grayscale framework
* Core functions
*
* This is a generic framework to use grayscale display within Rockbox
* plugins. It obviously does not work for the player.
*
* Copyright (C) 2004 Jens Arnold
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef SIMULATOR /* not for simulator by now */
#include "plugin.h"
#ifdef HAVE_LCD_BITMAP /* and also not for the Player */
#include "gray.h"
/* Global variables */
struct plugin_api *_gray_rb = NULL; /* global api struct pointer */
_tGraybuf *_graybuf = NULL; /* pointer to grayscale buffer */
short _gray_random_buffer; /* buffer for random number generator */
/* Prototypes */
static void _timer_isr(void);
/* timer interrupt handler: display next bitplane */
static void _timer_isr(void)
{
_gray_rb->lcd_blit(_graybuf->data + MULU16(_graybuf->plane_size,
_graybuf->cur_plane), _graybuf->x, _graybuf->by,
_graybuf->width, _graybuf->bheight, _graybuf->width);
if (++_graybuf->cur_plane >= _graybuf->depth)
_graybuf->cur_plane = 0;
if (_graybuf->flags & _GRAY_DEFERRED_UPDATE) /* lcd_update() requested? */
{
int x1 = MAX(_graybuf->x, 0);
int x2 = MIN(_graybuf->x + _graybuf->width, LCD_WIDTH);
int y1 = MAX(_graybuf->by << 3, 0);
int y2 = MIN((_graybuf->by << 3) + _graybuf->height, LCD_HEIGHT);
if (y1 > 0) /* refresh part above overlay, full width */
_gray_rb->lcd_update_rect(0, 0, LCD_WIDTH, y1);
if (y2 < LCD_HEIGHT) /* refresh part below overlay, full width */
_gray_rb->lcd_update_rect(0, y2, LCD_WIDTH, LCD_HEIGHT - y2);
if (x1 > 0) /* refresh part to the left of overlay */
_gray_rb->lcd_update_rect(0, y1, x1, y2 - y1);
if (x2 < LCD_WIDTH) /* refresh part to the right of overlay */
_gray_rb->lcd_update_rect(x2, y1, LCD_WIDTH - x2, y2 - y1);
_graybuf->flags &= ~_GRAY_DEFERRED_UPDATE; /* clear request */
}
}
/*---------------------------------------------------------------------------
Initialize the framework
----------------------------------------------------------------------------
Every framework needs such a function, and it has to be called as
the very first one */
void gray_init(struct plugin_api* newrb)
{
_gray_rb = newrb;
}
/*---------------------------------------------------------------------------
Prepare the grayscale display buffer
----------------------------------------------------------------------------
arguments:
gbuf = pointer to the memory area to use (e.g. plugin buffer)
gbuf_size = max usable size of the buffer
width = width in pixels (1..112)
bheight = height in 8-pixel units (1..8)
depth = desired number of shades - 1 (1..32)
result:
= depth if there was enough memory
< depth if there wasn't enough memory. The number of displayable
shades is smaller than desired, but it still works
= 0 if there wasn't even enough memory for 1 bitplane (black & white)
You can request any depth from 1 to 32, not just powers of 2. The routine
performs "graceful degradation" if the memory is not sufficient for the
desired depth. As long as there is at least enough memory for 1 bitplane,
it creates as many bitplanes as fit into memory, although 1 bitplane will
only deliver black & white display.
If you need info about the memory taken by the grayscale buffer, supply an
int* as the last parameter. This int will then contain the number of bytes
used. The total memory needed can be calculated as follows:
total_mem =
sizeof(_tGraybuf) (= 64 bytes currently)
+ sizeof(long) (= 4 bytes)
+ (width * bheight + sizeof(long)) * depth
+ 0..3 (longword alignment of grayscale display buffer)
*/
int gray_init_buffer(unsigned char *gbuf, int gbuf_size, int width,
int bheight, int depth, int *buf_taken)
{
int possible_depth, plane_size;
int i, j, align;
if ((unsigned) width > LCD_WIDTH
|| (unsigned) bheight > (LCD_HEIGHT/8)
|| depth < 1)
return 0;
/* the buffer has to be long aligned */
align = 3 - (((unsigned long)gbuf + 3) & 3);
gbuf += align;
gbuf_size -= align;
plane_size = MULU16(width, bheight);
possible_depth = (gbuf_size - sizeof(_tGraybuf) - sizeof(long))
/ (plane_size + sizeof(long));
if (possible_depth < 1)
return 0;
depth = MIN(depth, 32);
depth = MIN(depth, possible_depth);
_graybuf = (_tGraybuf *) gbuf; /* global pointer to buffer structure */
_graybuf->x = 0;
_graybuf->by = 0;
_graybuf->width = width;
_graybuf->height = bheight << 3;
_graybuf->bheight = bheight;
_graybuf->plane_size = plane_size;
_graybuf->depth = depth;
_graybuf->cur_plane = 0;
_graybuf->flags = 0;
_graybuf->bitpattern = (unsigned long *) (gbuf + sizeof(_tGraybuf));
_graybuf->data = (unsigned char *) (_graybuf->bitpattern + depth + 1);
i = depth - 1;
j = 8;
while (i != 0)
{
i >>= 1;
j--;
}
_graybuf->randmask = 0xFFu >> j;
/* initial state is all white */
_gray_rb->memset(_graybuf->data, 0, MULU16(depth, plane_size));
/* Precalculate the bit patterns for all possible pixel values */
for (i = 0; i <= depth; i++)
{
unsigned long pattern = 0;
int value = 0;
for (j = 0; j < depth; j++)
{
pattern <<= 1;
value += i;
if (value >= depth)
value -= depth; /* "white" bit */
else
pattern |= 1; /* "black" bit */
}
/* now the lower <depth> bits contain the pattern */
_graybuf->bitpattern[i] = pattern;
}
_graybuf->fg_pattern = _graybuf->bitpattern[0]; /* black */
_graybuf->bg_pattern = _graybuf->bitpattern[depth]; /* white */
_graybuf->drawmode = GRAY_DRAW_SOLID;
_graybuf->curfont = FONT_SYSFIXED;
if (buf_taken) /* caller requested info about space taken */
{
*buf_taken = sizeof(_tGraybuf) + sizeof(long)
+ MULU16(plane_size + sizeof(long), depth) + align;
}
return depth;
}
/*---------------------------------------------------------------------------
Release the grayscale display buffer
----------------------------------------------------------------------------
Switches the grayscale overlay off at first if it is still running,
then sets the pointer to NULL.
DO CALL either this function or at least gray_show_display(false)
before you exit, otherwise nasty things may happen.
*/
void gray_release_buffer(void)
{
gray_show_display(false);
_graybuf = NULL;
}
/*---------------------------------------------------------------------------
Switch the grayscale overlay on or off
----------------------------------------------------------------------------
enable = true: the grayscale overlay is switched on if initialized
= false: the grayscale overlay is switched off and the regular lcd
content is restored
DO NOT call lcd_update() or any other api function that directly accesses
the lcd while the grayscale overlay is running! If you need to do
lcd_update() to update something outside the grayscale overlay area, use
gray_deferred_update() instead.
Other functions to avoid are:
lcd_blit() (obviously), lcd_update_rect(), lcd_set_contrast(),
lcd_set_invert_display(), lcd_set_flip(), lcd_roll()
The grayscale display consumes ~50 % CPU power (for a full screen overlay,
less if the overlay is smaller) when switched on. You can switch the overlay
on and off as many times as you want.
*/
void gray_show_display(bool enable)
{
if (enable)
{
_graybuf->flags |= _GRAY_RUNNING;
_gray_rb->plugin_register_timer(FREQ / 67, 1, _timer_isr);
}
else
{
_gray_rb->plugin_unregister_timer();
_graybuf->flags &= ~_GRAY_RUNNING;
_gray_rb->lcd_update(); /* restore whatever there was before */
}
}
#endif // #ifdef HAVE_LCD_BITMAP
#endif // #ifndef SIMULATOR
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