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Greyscale library: Preparations for a gamma measurement plugin.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16492 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Jens Arnold 2008-03-02 23:31:09 +00:00
parent 8abe9cffe4
commit 8493f5bcf6
12 changed files with 41 additions and 24 deletions
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8
apps/plugins/lib/grey.h
View file

@ -29,8 +29,10 @@
#if defined(HAVE_LCD_BITMAP) && (LCD_DEPTH < 4)
/* The greyscale lib uses 8 bit brightness values natively on input. */
#define GREY_BRIGHTNESS(y) (y)
/* Some predefined levels for convenience: */
#define GREY_BLACK GREY_BRIGHTNESS(0)
#define GREY_DARKGRAY GREY_BRIGHTNESS(85)
#define GREY_LIGHTGRAY GREY_BRIGHTNESS(170)
@ -42,9 +44,13 @@
#define GREY_INFO_STRUCT struct _grey_info _grey_info;
#define GREY_INFO_STRUCT_IRAM struct _grey_info _grey_info IBSS_ATTR;
/* Features you can request on library init (ORed together): */
#define GREY_BUFFERED 0x0001
#define GREY_RAWMAPPED 0x0002
/* Library initialisation and release */
bool grey_init(struct plugin_api* newrb, unsigned char *gbuf, long gbuf_size,
bool buffered, int width, int height, long *buf_taken);
unsigned features, int width, int height, long *buf_taken);
void grey_release(void);
/* Special functions */

31
apps/plugins/lib/grey_core.c
View file

@ -312,10 +312,12 @@ static int log_s16p16(int x)
newrb = pointer to plugin api
gbuf = pointer to the memory area to use (e.g. plugin buffer)
gbuf_size = max usable size of the buffer
buffered = use chunky pixel buffering?
features = flags for requesting features
GREY_BUFFERED: use chunky pixel buffering
This allows to use all drawing functions, but needs more
memory. Unbuffered operation provides only a subset of
drawing functions. (only grey_bitmap drawing and scrolling)
GREY_RAWMAPPED: no LCD linearisation and gamma correction
width = width in pixels (1..LCD_WIDTH)
height = height in pixels (1..LCD_HEIGHT)
Note that depending on the target LCD, either height or
@ -335,7 +337,7 @@ static int log_s16p16(int x)
The function is authentic regarding memory usage on the simulator, even
if it doesn't use all of the allocated memory. */
bool grey_init(struct plugin_api* newrb, unsigned char *gbuf, long gbuf_size,
bool buffered, int width, int height, long *buf_taken)
unsigned features, int width, int height, long *buf_taken)
{
int bdim, i;
long plane_size, buftaken;
@ -372,7 +374,7 @@ bool grey_init(struct plugin_api* newrb, unsigned char *gbuf, long gbuf_size,
#endif
gbuf += buftaken;
if (buffered) /* chunky buffer */
if (features & GREY_BUFFERED) /* chunky buffer */
{
_grey_info.buffer = gbuf;
gbuf += plane_size;
@ -418,14 +420,21 @@ bool grey_init(struct plugin_api* newrb, unsigned char *gbuf, long gbuf_size,
/* precalculate the value -> pattern index conversion table, taking
linearisation and gamma correction into account */
for (i = 0; i < 256; i++)
{
data = exp_s16p16(((2<<8) * log_s16p16(i * 257 + 1)) >> 8) + 128;
data = (data - (data >> 8)) >> 8; /* approx. data /= 257 */
data = (lcdlinear[data] << 7) + 127;
_grey_info.gvalue[i] = (data + (data >> 8)) >> 8;
if (features & GREY_RAWMAPPED)
for (i = 0; i < 256; i++)
{
data = i << 7;
_grey_info.gvalue[i] = (data + (data >> 8)) >> 8;
}
else
for (i = 0; i < 256; i++)
{
data = exp_s16p16(((2<<8) * log_s16p16(i * 257 + 1)) >> 8) + 128;
data = (data - (data >> 8)) >> 8; /* approx. data /= 257 */
data = (lcdlinear[data] << 7) + 127;
_grey_info.gvalue[i] = (data + (data >> 8)) >> 8;
/* approx. data / 255 */
}
}
if (buf_taken) /* caller requested info about space taken */
*buf_taken = buftaken;
@ -469,7 +478,7 @@ void grey_show(bool enable)
_grey_info.rb->timer_register(1, NULL, TIMER_FREQ / 70, 1, _timer_isr);
#elif CONFIG_LCD == LCD_IPOD2BPP
#ifdef IPOD_1G2G
_grey_info.rb->timer_register(1, NULL, TIMER_FREQ / 95, 1, _timer_isr); /* verified */
_grey_info.rb->timer_register(1, NULL, TIMER_FREQ / 96, 1, _timer_isr); /* verified */
#elif defined IPOD_3G
_grey_info.rb->timer_register(1, NULL, TIMER_FREQ / 87, 1, _timer_isr); /* verified */
#else