From 628d20a6109bf65175e7c4b1bd9477cdccfd7437 Mon Sep 17 00:00:00 2001 From: Jens Arnold Date: Wed, 2 Aug 2006 00:22:01 +0000 Subject: Grayscale library: LCD linearisation and gamma correction. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@10402 a1c6a512-1295-4272-9138-f99709370657 --- apps/plugins/lib/gray_core.c | 216 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 212 insertions(+), 4 deletions(-) (limited to 'apps/plugins/lib/gray_core.c') diff --git a/apps/plugins/lib/gray_core.c b/apps/plugins/lib/gray_core.c index 6cc33e05da..ef41e7e215 100644 --- a/apps/plugins/lib/gray_core.c +++ b/apps/plugins/lib/gray_core.c @@ -33,7 +33,117 @@ struct plugin_api *_gray_rb = NULL; /* global api struct pointer */ struct _gray_info _gray_info; /* global info structure */ #ifndef SIMULATOR short _gray_random_buffer; /* buffer for random number generator */ + +#if CONFIG_LCD == LCD_SSD1815 +/* measured and interpolated curve */ +static const unsigned char lcdlinear[256] = { + 0, 3, 5, 8, 11, 13, 16, 18, + 21, 23, 26, 28, 31, 33, 36, 38, + 40, 42, 45, 47, 49, 51, 53, 55, + 57, 59, 60, 62, 64, 66, 67, 69, + 70, 72, 73, 74, 76, 77, 78, 79, + 81, 82, 83, 84, 85, 86, 87, 88, + 88, 89, 90, 91, 92, 92, 93, 94, + 95, 95, 96, 97, 97, 98, 99, 99, + 100, 101, 102, 102, 103, 104, 104, 105, + 106, 106, 107, 107, 108, 109, 109, 110, + 111, 111, 112, 113, 113, 114, 114, 115, + 116, 116, 117, 117, 118, 119, 119, 120, + 120, 121, 121, 122, 122, 123, 123, 124, + 124, 125, 125, 126, 126, 127, 127, 128, + 128, 128, 129, 129, 130, 130, 131, 131, + 132, 132, 133, 133, 133, 134, 134, 135, + 135, 136, 136, 137, 137, 138, 138, 138, + 139, 139, 140, 140, 141, 141, 142, 142, + 143, 143, 144, 144, 145, 145, 146, 146, + 147, 147, 148, 148, 148, 149, 149, 150, + 150, 151, 151, 152, 152, 153, 153, 153, + 154, 154, 155, 155, 156, 156, 157, 157, + 158, 158, 158, 159, 159, 160, 160, 161, + 161, 162, 162, 163, 163, 164, 164, 165, + 165, 166, 167, 167, 168, 168, 169, 169, + 170, 171, 171, 172, 173, 173, 174, 175, + 176, 176, 177, 178, 179, 180, 181, 181, + 182, 183, 184, 185, 186, 188, 189, 190, + 191, 192, 194, 195, 196, 198, 199, 201, + 202, 204, 205, 207, 209, 211, 213, 215, + 217, 219, 222, 224, 226, 229, 231, 234, + 236, 239, 242, 244, 247, 250, 252, 255 +}; +#elif CONFIG_LCD == LCD_S1D15E06 +/* measured and interpolated curve */ +static const unsigned char lcdlinear[256] = { + 0, 5, 11, 16, 21, 27, 32, 37, + 42, 47, 51, 56, 60, 64, 68, 72, + 75, 78, 81, 84, 87, 89, 91, 93, + 95, 96, 98, 99, 101, 102, 103, 104, + 105, 106, 107, 108, 109, 110, 111, 111, + 112, 113, 113, 114, 115, 115, 116, 117, + 117, 118, 118, 119, 119, 120, 120, 121, + 121, 122, 122, 123, 123, 124, 124, 125, + 125, 126, 126, 127, 127, 127, 128, 128, + 129, 129, 130, 130, 131, 131, 132, 132, + 133, 133, 134, 134, 135, 135, 136, 136, + 137, 137, 138, 138, 138, 139, 139, 140, + 140, 141, 141, 141, 142, 142, 143, 143, + 143, 144, 144, 145, 145, 145, 146, 146, + 146, 147, 147, 147, 148, 148, 149, 149, + 149, 150, 150, 150, 151, 151, 151, 152, + 152, 153, 153, 153, 154, 154, 155, 155, + 155, 156, 156, 157, 157, 157, 158, 158, + 159, 159, 159, 160, 160, 161, 161, 162, + 162, 162, 163, 163, 164, 164, 164, 165, + 165, 166, 166, 167, 167, 167, 168, 168, + 169, 169, 170, 170, 170, 171, 171, 172, + 172, 173, 173, 174, 174, 175, 175, 176, + 176, 177, 177, 178, 178, 179, 179, 180, + 180, 181, 182, 182, 183, 184, 184, 185, + 186, 186, 187, 188, 188, 189, 190, 191, + 191, 192, 193, 194, 195, 196, 196, 197, + 198, 199, 200, 201, 202, 203, 204, 205, + 206, 207, 208, 209, 210, 211, 213, 214, + 215, 216, 218, 219, 220, 222, 223, 225, + 227, 228, 230, 232, 233, 235, 237, 239, + 241, 243, 245, 247, 249, 251, 253, 255 +}; #endif +#else /* SIMULATOR */ +/* undo a (generic) PC display gamma of 2.0 to simulate target behaviour */ +static const unsigned char lcdlinear[256] = { + 0, 16, 23, 28, 32, 36, 39, 42, + 45, 48, 50, 53, 55, 58, 60, 62, + 64, 66, 68, 70, 71, 73, 75, 77, + 78, 80, 81, 83, 84, 86, 87, 89, + 90, 92, 93, 94, 96, 97, 98, 100, + 101, 102, 103, 105, 106, 107, 108, 109, + 111, 112, 113, 114, 115, 116, 117, 118, + 119, 121, 122, 123, 124, 125, 126, 127, + 128, 129, 130, 131, 132, 133, 134, 135, + 135, 136, 137, 138, 139, 140, 141, 142, + 143, 144, 145, 145, 146, 147, 148, 149, + 150, 151, 151, 152, 153, 154, 155, 156, + 156, 157, 158, 159, 160, 160, 161, 162, + 163, 164, 164, 165, 166, 167, 167, 168, + 169, 170, 170, 171, 172, 173, 173, 174, + 175, 176, 176, 177, 178, 179, 179, 180, + 181, 181, 182, 183, 183, 184, 185, 186, + 186, 187, 188, 188, 189, 190, 190, 191, + 192, 192, 193, 194, 194, 195, 196, 196, + 197, 198, 198, 199, 199, 200, 201, 201, + 202, 203, 203, 204, 204, 205, 206, 206, + 207, 208, 208, 209, 209, 210, 211, 211, + 212, 212, 213, 214, 214, 215, 215, 216, + 217, 217, 218, 218, 219, 220, 220, 221, + 221, 222, 222, 223, 224, 224, 225, 225, + 226, 226, 227, 228, 228, 229, 229, 230, + 230, 231, 231, 232, 233, 233, 234, 234, + 235, 235, 236, 236, 237, 237, 238, 238, + 239, 240, 240, 241, 241, 242, 242, 243, + 243, 244, 244, 245, 245, 246, 246, 247, + 247, 248, 248, 249, 249, 250, 250, 251, + 251, 252, 252, 253, 253, 254, 254, 255 +}; +#endif /* SIMULATOR */ /* Prototypes */ static inline void _deferred_update(void) __attribute__ ((always_inline)); @@ -84,6 +194,75 @@ static void _timer_isr(void) } #endif /* !SIMULATOR */ +/* fixed point exp() */ +static int exp_s16p16(int x) +{ + int t; + int y = 0x00010000; + + if (x == 0) + { + return y; + } + else if (x > 0) + { + t = x - 0x58b91; if (t >= 0) x = t, y <<= 8; + t = x - 0x2c5c8; if (t >= 0) x = t, y <<= 4; + t = x - 0x162e4; if (t >= 0) x = t, y <<= 2; + t = x - 0x0b172; if (t >= 0) x = t, y <<= 1; + } + else + { + t = x + 0x58b91; if (t < 0) x = t, y >>= 8; + t = x + 0x2c5c8; if (t < 0) x = t, y >>= 4; + t = x + 0x162e4; if (t < 0) x = t, y >>= 2; + t = x + 0x0b172; if (t < 0) x = t, y >>= 1; + x += 0x0b172; y >>= 1; + } + t = x - 0x067cd; if (t >= 0) x = t, y += y >> 1; + t = x - 0x03920; if (t >= 0) x = t, y += y >> 2; + t = x - 0x01e27; if (t >= 0) x = t, y += y >> 3; + t = x - 0x00f85; if (t >= 0) x = t, y += y >> 4; + t = x - 0x007e1; if (t >= 0) x = t, y += y >> 5; + t = x - 0x003f8; if (t >= 0) x = t, y += y >> 6; + t = x - 0x001fe; if (t >= 0) x = t, y += y >> 7; + if (x & 0x100) y += y >> 8; + if (x & 0x080) y += y >> 9; + if (x & 0x040) y += y >> 10; + if (x & 0x020) y += y >> 11; + if (x & 0x010) y += y >> 12; + if (x & 0x008) y += y >> 13; + if (x & 0x004) y += y >> 14; + if (x & 0x002) y += y >> 15; + if (x & 0x001) y += y >> 16; + + return y; +} + +/* fixed point log() */ +int log_s16p16(int x) +{ + int t; + int y = 0xa65af; + + if (x < 0x00008000) x <<=16, y -= 0xb1721; + if (x < 0x00800000) x <<= 8, y -= 0x58b91; + if (x < 0x08000000) x <<= 4, y -= 0x2c5c8; + if (x < 0x20000000) x <<= 2, y -= 0x162e4; + if (x < 0x40000000) x <<= 1, y -= 0x0b172; + t = x + (x >> 1); if ((t & 0x80000000) == 0) x = t, y -= 0x067cd; + t = x + (x >> 2); if ((t & 0x80000000) == 0) x = t, y -= 0x03920; + t = x + (x >> 3); if ((t & 0x80000000) == 0) x = t, y -= 0x01e27; + t = x + (x >> 4); if ((t & 0x80000000) == 0) x = t, y -= 0x00f85; + t = x + (x >> 5); if ((t & 0x80000000) == 0) x = t, y -= 0x007e1; + t = x + (x >> 6); if ((t & 0x80000000) == 0) x = t, y -= 0x003f8; + t = x + (x >> 7); if ((t & 0x80000000) == 0) x = t, y -= 0x001fe; + x = 0x80000000 - x; + y -= x >> 15; + + return y; +} + /* Initialise the framework and prepare the greyscale display buffer arguments: @@ -97,6 +276,8 @@ static void _timer_isr(void) width = width in pixels (1..LCD_WIDTH) bheight = height in LCD pixel-block units (8 pixels) (1..LCD_HEIGHT/8) depth = number of bitplanes to use (1..32). + gamma = gamma value as s8p8 fixed point. gamma <= 0 means no + correction at all, i.e. no LCD linearisation as well. result: = depth if there was enough memory @@ -128,12 +309,14 @@ static void _timer_isr(void) one situation where it will consume more memory on the sim than on the target: if you're allocating a low depth (< 8) without buffering. */ int gray_init(struct plugin_api* newrb, unsigned char *gbuf, long gbuf_size, - bool buffered, int width, int bheight, int depth, long *buf_taken) + bool buffered, int width, int bheight, int depth, int gamma, + long *buf_taken) { - int possible_depth; + int possible_depth, i; long plane_size, buftaken; + unsigned data; #ifndef SIMULATOR - int i, j; + int j; #endif _gray_rb = newrb; @@ -240,8 +423,33 @@ int gray_init(struct plugin_api* newrb, unsigned char *gbuf, long gbuf_size, } #endif + /* precalculate the value -> pattern index conversion table, taking + linearisation and gamma correction into account */ + if (gamma <= 0) + { + for (i = 0; i < 256; i++) + { + data = MULU16(depth, lcdlinear[i]) + 127; + _gray_info.idxtable[i] = (data + (data >> 8)) >> 8; + /* approx. data / 255 */ + } + } + else + { + for (i = 0; i < 256; i++) + { + data = exp_s16p16(gamma * (log_s16p16(i * 257 + 1) >> 8)); + data = (data - (data >> 8)) >> 8; /* approx. data /= 257 */ + data = MULU16(depth, lcdlinear[data]) + 127; + _gray_info.idxtable[i] = (data + (data >> 8)) >> 8; + /* approx. data / 255 */ + } + } + + _gray_info.fg_index = 0; + _gray_info.bg_index = depth; _gray_info.fg_brightness = 0; - _gray_info.bg_brightness = depth; + _gray_info.bg_brightness = 255; _gray_info.drawmode = DRMODE_SOLID; _gray_info.curfont = FONT_SYSFIXED; -- cgit v1.2.3