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ii-pix
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Flatten image array, about 5% faster

This commit is contained in:
kris 2021-01-22 22:19:48 +00:00
parent 61e1448b87
commit 081c815643
1 changed files with 29 additions and 9 deletions
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38
dither.pyx
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@ -9,12 +9,18 @@ from libc.stdlib cimport malloc, free
# TODO: use a cdef class
cdef struct Dither:
float* pattern
float* pattern # Flattened dither pattern
int x_shape
int y_shape
int x_origin
int y_origin
cdef struct Image:
float* flat # Flattened image array
int shape0
int shape1
int shape2
@cython.boundscheck(False)
@cython.wraparound(False)
@ -36,7 +42,7 @@ cdef void apply_one_line(Dither* dither, int xl, int xr, int x, float[] image, i
@cython.boundscheck(False)
@cython.wraparound(False)
cdef apply(Dither* dither, screen, int x, int y, float [:, :, ::1]image, float[] quant_error):
cdef apply(Dither* dither, screen, int x, int y, Image* image, float[] quant_error):
cdef int i, j, k
cdef int yt = dither_bounds_yt(dither, y)
@ -53,7 +59,8 @@ cdef apply(Dither* dither, screen, int x, int y, float [:, :, ::1]image, float[]
for j in range(xl, xr):
for k in range(3):
error = dither.pattern[(i - y) * dither.x_shape + j - x + dither.x_origin] * quant_error[k]
image[i, j, k] = clip(image[i, j, k] + error, 0, 255)
image.flat[i * image.shape1 * image.shape2 + j * image.shape2 + k] = clip(
image.flat[i * image.shape1 * image.shape2 + j * image.shape2 + k] + error, 0, 255)
@cython.boundscheck(False)
@ -88,7 +95,7 @@ cdef int dither_bounds_yb(Dither *dither, int y_res, int y):
@cython.boundscheck(False)
@cython.wraparound(False)
cdef dither_lookahead(Dither* dither,
screen, float[:,:,::1] image_rgb, int x, int y, unsigned char[:, ::1] options_4bit,
screen, Image* image_rgb, int x, int y, unsigned char[:, ::1] options_4bit,
float[:, :, ::1] options_rgb, int lookahead):
cdef int x_res = screen.X_RES
@ -107,7 +114,8 @@ cdef dither_lookahead(Dither* dither,
# Copies of input pixels so we can dither in bulk
for j in range(xxr - x):
for k in range(3):
lah_image_rgb[i * lah_shape1 * lah_shape2 + j * lah_shape2 + k] = image_rgb[y, x+j, k]
lah_image_rgb[i * lah_shape1 * lah_shape2 + j * lah_shape2 + k] = image_rgb.flat[
y * image_rgb.shape1 * image_rgb.shape2 + (x+j) * image_rgb.shape2 + k]
# Leave enough space at right of image so we can dither the last of our lookahead pixels.
for j in range(xxr - x, lookahead + xr - xl):
for k in range(3):
@ -213,7 +221,7 @@ def dither_image(screen, float[:, :, ::1] image_rgb, dither, int lookahead):
cdef (unsigned char)[:, ::1] options_4bit
cdef float[:, :, ::1] options_rgb
cdef unsigned char output_pixel_4bit
cdef float[::1] input_pixel_rgb
cdef float[3] input_pixel_rgb
cdef Dither cdither
cdither.y_shape = dither.PATTERN.shape[0]
@ -226,16 +234,27 @@ def dither_image(screen, float[:, :, ::1] image_rgb, dither, int lookahead):
for j in range(cdither.x_shape):
cdither.pattern[i * cdither.x_shape + j] = dither.PATTERN[i, j, 0]
cdef Image image
image.flat = <float *> malloc(image_rgb.shape[0] * image_rgb.shape[1] * image_rgb.shape[2] * sizeof(float))
image.shape0 = image_rgb.shape[0]
image.shape1 = image_rgb.shape[1]
image.shape2 = image_rgb.shape[2]
for y in range(image.shape0):
for x in range(image.shape1):
for i in range(image.shape2):
image.flat[y * image.shape1 * image.shape2 + x * image.shape2 + i] = image_rgb[y, x, i]
for y in range(yres):
output_pixel_4bit = 0
for x in range(xres):
input_pixel_rgb = image_rgb[y, x, :]
for i in range(3):
input_pixel_rgb[i] = image.flat[y * image.shape1 * image.shape2 + x * image.shape2 + i]
if lookahead:
palette_choices_4bit, palette_choices_rgb = lookahead_options(
screen, lookahead, output_pixel_4bit, x % 4)
output_pixel_4bit, output_pixel_rgb = \
dither_lookahead(
&cdither, screen, image_rgb, x, y, palette_choices_4bit, palette_choices_rgb, lookahead)
&cdither, screen, &image, x, y, palette_choices_4bit, palette_choices_rgb, lookahead)
else:
palette_choices_4bit, palette_choices_rgb = screen.pixel_palette_options(output_pixel_4bit, x)
output_pixel_4bit, output_pixel_rgb = \
@ -243,9 +262,10 @@ def dither_image(screen, float[:, :, ::1] image_rgb, dither, int lookahead):
for i in range(3):
quant_error[i] = input_pixel_rgb[i] - output_pixel_rgb[i]
image_4bit[y, x] = output_pixel_4bit
apply(&cdither, screen, x, y, image_rgb, quant_error)
apply(&cdither, screen, x, y, &image, quant_error)
for i in range(3):
image_rgb[y, x, i] = output_pixel_rgb[i]
free(cdither.pattern)
free(image.flat)
return image_4bit, np.array(image_rgb)