Add support for drawing the SMPTE pattern in a buffer using the C1
indexed format.
As only two colors are available, the pattern is drawn in black and
white, using Floyd-Steinberg dithering.
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
v2:
New.
---
tests/util/pattern.c | 171 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 167 insertions(+), 4 deletions(-)
diff --git a/tests/util/pattern.c b/tests/util/pattern.c
index 8ed5f8dd1a6282f9..5ec7d66495209df4 100644
--- a/tests/util/pattern.c
+++ b/tests/util/pattern.c
@@ -668,6 +668,163 @@ static unsigned int smpte_bottom[8] = {
SMPTE_COLOR_BLACK,
};
+/*
+ * Floyd-Steinberg dithering
+ */
+
+struct fsd {
+ unsigned int width;
+ unsigned int x;
+ unsigned int i;
+ int red;
+ int green;
+ int blue;
+ int error[];
+};
+
+static struct fsd *fsd_alloc(unsigned int width)
+{
+ unsigned int n = 3 * (width + 1);
+ struct fsd *fsd = malloc(sizeof(*fsd) + n * sizeof(fsd->error[0]));
+
+ fsd->width = width;
+ fsd->x = 0;
+ fsd->i = 0;
+ memset(fsd->error, 0, n * sizeof(fsd->error[0]));
+
+ return fsd;
+}
+
+static inline int clamp(int val, int min, int max)
+{
+ if (val < min)
+ return min;
+ if (val > max)
+ return max;
+ return val;
+}
+
+static void fsd_dither(struct fsd *fsd, struct drm_color_lut *color)
+{
+ unsigned int i = fsd->i;
+
+ fsd->red = (int)color->red + (fsd->error[3 * i] + 8) / 16;
+ fsd->green = (int)color->green + (fsd->error[3 * i + 1] + 8) / 16;
+ fsd->blue = (int)color->blue + (fsd->error[3 * i + 2] + 8) / 16;
+
+ color->red = clamp(fsd->red, 0, 65535);
+ color->green = clamp(fsd->green, 0, 65535);
+ color->blue = clamp(fsd->blue, 0, 65535);
+}
+
+static void fsd_update(struct fsd *fsd, const struct drm_color_lut *actual)
+{
+ int error_red = fsd->red - (int)actual->red;
+ int error_green = fsd->green - (int)actual->green;
+ int error_blue = fsd->blue - (int)actual->blue;
+ unsigned int width = fsd->width;
+ unsigned int i = fsd->i, j;
+ unsigned int n = width + 1;
+
+ /* Distribute errors over neighboring pixels */
+ if (fsd->x == width - 1) {
+ /* Last pixel on this scanline */
+ /* South East: initialize to zero */
+ fsd->error[3 * i] = 0;
+ fsd->error[3 * i + 1] = 0;
+ fsd->error[3 * i + 2] = 0;
+ } else {
+ /* East: accumulate error */
+ j = (i + 1) % n;
+ fsd->error[3 * j] += 7 * error_red;
+ fsd->error[3 * j + 1] += 7 * error_green;
+ fsd->error[3 * j + 2] += 7 * error_blue;
+
+ /* South East: initial error */
+ fsd->error[3 * i] = error_red;
+ fsd->error[3 * i + 1] = error_green;
+ fsd->error[3 * i + 2] = error_blue;
+ }
+ /* South West: accumulate error */
+ j = (i + width - 1) % n;
+ fsd->error[3 * j] += 3 * error_red;
+ fsd->error[3 * j + 1] += 3 * error_green;
+ fsd->error[3 * j + 2] += 3 * error_blue;
+
+ /* South: accumulate error */
+ j = (i + width) % n;
+ fsd->error[3 * j] += 5 * error_red;
+ fsd->error[3 * j + 1] += 5 * error_green;
+ fsd->error[3 * j + 2] += 5 * error_blue;
+
+ fsd->x = (fsd->x + 1) % width;
+ fsd->i = (fsd->i + 1) % n;
+}
+
+static void write_pixel_1(uint8_t *mem, unsigned int x, unsigned int pixel)
+{
+ unsigned int shift = 7 - (x & 7);
+ unsigned int mask = 1U << shift;
+
+ mem[x / 8] = (mem[x / 8] & ~mask) | ((pixel << shift) & mask);
+}
+
+static void write_color_1(struct fsd *fsd, uint8_t *mem, unsigned int x,
+ unsigned int index)
+{
+ struct drm_color_lut color = smpte_color_lut[index];
+ unsigned int pixel;
+
+ fsd_dither(fsd, &color);
+
+ /* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */
+ if (3 * color.red + 6 * color.green + color.blue >= 10 * 32768) {
+ pixel = 1;
+ color.red = color.green = color.blue = 65535;
+ } else {
+ pixel = 0;
+ color.red = color.green = color.blue = 0;
+ }
+
+ fsd_update(fsd, &color);
+
+ write_pixel_1(mem, x, pixel);
+}
+
+static void fill_smpte_c1(void *mem, unsigned int width, unsigned int height,
+ unsigned int stride)
+{
+ struct fsd *fsd = fsd_alloc(width);
+ unsigned int x;
+ unsigned int y;
+
+ for (y = 0; y < height * 6 / 9; ++y) {
+ for (x = 0; x < width; ++x)
+ write_color_1(fsd, mem, x, smpte_top[x * 7 / width]);
+ mem += stride;
+ }
+
+ for (; y < height * 7 / 9; ++y) {
+ for (x = 0; x < width; ++x)
+ write_color_1(fsd, mem, x, smpte_middle[x * 7 / width]);
+ mem += stride;
+ }
+
+ for (; y < height; ++y) {
+ for (x = 0; x < width * 5 / 7; ++x)
+ write_color_1(fsd, mem, x,
+ smpte_bottom[x * 4 / (width * 5 / 7)]);
+ for (; x < width * 6 / 7; ++x)
+ write_color_1(fsd, mem, x,
+ smpte_bottom[(x - width * 5 / 7) * 3 /
+ (width / 7) + 4]);
+ for (; x < width; ++x)
+ write_color_1(fsd, mem, x, smpte_bottom[7]);
+ mem += stride;
+ }
+
+ free(fsd);
+}
static void write_pixel_4(uint8_t *mem, unsigned int x, unsigned int pixel)
{
if (x & 1)
@@ -742,9 +899,8 @@ static void fill_smpte_c8(void *mem, unsigned int width, unsigned int height,
void util_smpte_index_gamma(unsigned size, struct drm_color_lut *lut)
{
- if (size < ARRAY_SIZE(smpte_color_lut)) {
- printf("Error: gamma too small: %u < %zu\n", size,
- ARRAY_SIZE(smpte_color_lut));
+ if (size < 2) {
+ printf("Error: gamma too small: %u < 2\n", size);
return;
}
memset(lut, 0, size * sizeof(struct drm_color_lut));
@@ -754,7 +910,12 @@ void util_smpte_index_gamma(unsigned size, struct drm_color_lut *lut)
lut[idx].green = (g) * 0x101; \
lut[idx].blue = (b) * 0x101
- memcpy(lut, smpte_color_lut, sizeof(smpte_color_lut));
+ if (size < ARRAY_SIZE(smpte_color_lut)) {
+ FILL_COLOR(0, 0, 0, 0 ); /* black */
+ FILL_COLOR(1, 255, 255, 255); /* white */
+ } else {
+ memcpy(lut, smpte_color_lut, sizeof(smpte_color_lut));
+ }
#undef FILL_COLOR
}
@@ -766,6 +927,8 @@ static void fill_smpte(const struct util_format_info *info, void *planes[3],
unsigned char *u, *v;
switch (info->format) {
+ case DRM_FORMAT_C1:
+ return fill_smpte_c1(planes[0], width, height, stride);
case DRM_FORMAT_C4:
return fill_smpte_c4(planes[0], width, height, stride);
case DRM_FORMAT_C8:
--
2.25.1
