diff options
| -rw-r--r-- | Makefile | 1 | ||||
| -rw-r--r-- | common.h | 5 | ||||
| -rw-r--r-- | demo.c | 12 | ||||
| -rw-r--r-- | draw_linear_bezier_reference.c | 111 | ||||
| -rw-r--r-- | rtgrpblib_draw_linear_bezier.c | 5 |
5 files changed, 129 insertions, 5 deletions
@@ -20,6 +20,7 @@ OBJ =\ equations.o\ lines.o\ sorting.o\ + draw_linear_bezier_reference.o\ rtgrpblib_create_raster.o\ rtgrpblib_draw_circular_arc.o\ rtgrpblib_draw_linear_bezier.o\ @@ -83,6 +83,11 @@ iszeroish(double x) +/* draw_linear_bezier_reference.c */ +#define draw_linear_bezier_reference rtgrpblib_draw_linear_bezier_reference__ +void draw_linear_bezier_reference(RASTER *restrict raster, double x1, double y1, double x2, double y2); + + /* equations.c */ #define solve_cubic rtgrpblib_solve_cubic__ #define solve_quadratic rtgrpblib_solve_quadratic__ @@ -21,12 +21,12 @@ main(void) {30, 15}, {20, 25}, {10, 15} -#elif 0 +#elif 1 {20, 5}, {35, 15}, {20, 25}, {5, 15} -#elif 0 +#elif 1 {5.25, 5.25}, {35.75, 5.25}, {35.75, 25.75}, @@ -42,16 +42,18 @@ main(void) raster = rtgrpblib_create_raster(width, height); image = calloc(width * height, sizeof(*image)); -#if 0 + rtgrpblib_set_draftness(raster, -1); + +#if 1 n = sizeof(points) / sizeof(*points); for (i = 0; i < n; i++) { j = (i + 1) % n; rtgrpblib_draw_linear_bezier(raster, P(i), P(j)); } -#elif 0 +#elif 1 rtgrpblib_draw_quadratic_bezier(raster, P(2), P(3), P(0)); rtgrpblib_draw_linear_bezier(raster, P(0), P(2)); -#elif 0 +#elif 1 rtgrpblib_draw_cubic_bezier(raster, P(0), P(1), P(2), P(3)); rtgrpblib_draw_linear_bezier(raster, P(3), P(0)); #else diff --git a/draw_linear_bezier_reference.c b/draw_linear_bezier_reference.c new file mode 100644 index 0000000..6066946 --- /dev/null +++ b/draw_linear_bezier_reference.c @@ -0,0 +1,111 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" +#ifndef TEST + +/* + * The implementation in this fill is not supposed to be fast, + * it is supposed to be absolutely correct. The implementation + * shall be as clear and obvious as possible. It is important + * that everything written to cells is as precise as possible + * and that the function behavious correctly when outside the + * raster. This implementation shall be usable to generate an + * as perfect as possible rasterisation and shall be usable to + * test the correctness and accuracy of the fast implementation. + */ + + +void +draw_linear_bezier_reference(RASTER *restrict raster, double x1, double y1, double x2, double y2) +{ + double dx = x2 - x1; + double dy = y2 - y1; + int xdir = SIGNUM(dx); + int ydir = SIGNUM(dy); + double kx = dx / dy; + double ky = dy / dx; + double prevX, prevY, x, y, cx, cy, h2x, h2y; + double xfloor, yfloor; + ssize_t cellX, cellY; + size_t cell; + + prevX = x1; + prevY = y1; + + for (; prevX != x2 && prevY != y2; prevX = x, prevY = y) { + /* Find next vertical and next hozitonal grid line */ + x = xdir < 0 ? floor(prevX) : xdir > 0 ? ceil(prevX) : prevX; + y = ydir < 0 ? floor(prevY) : ydir > 0 ? ceil(prevY) : prevY; + x = x == prevX ? x + xdir : x; + y = y == prevY ? y + ydir : y; + + /* Limit to the extend of the drawn line segment */ + if ((xdir < 0 && x < x2) || (xdir > 0 && x > x2)) + x = x2; + if ((ydir < 0 && y < y2) || (ydir > 0 && y > y2)) + y = y2; + + /* Find next cell edge */ + if (xdir && ydir) { + cy = y1 + (x - x1) * ky; + cx = x1 + (y - y1) * kx; + h2x = (cy - prevY) * (cy - prevY) + (x - prevX) * (x - prevX); + h2y = (cx - prevX) * (cx - prevX) + (y - prevY) * (y - prevY); + if (h2x < h2y) + y = cy; + else + x = cx; + + /* Make sure loop will exit when we reach the end */ + if ((xdir < 0 && x < x2) || (xdir > 0 && x > x2)) + x = x2; + if ((ydir < 0 && y < y2) || (ydir > 0 && y > y2)) + y = y2; + } + + /* Select cell to draw in */ + xfloor = xdir >= 0 ? floor(prevX) : floor(x); + yfloor = ydir >= 0 ? floor(prevY) : floor(y); + cellX = (ssize_t)xfloor; + cellY = (ssize_t)yfloor; + + /* Do not draw if above or below the raster*/ + if (cellY < 0 || (size_t)cellY >= raster->height) + continue; + + if (cellX < 0) { + /* Draw on first column in raster of outside of raster on the left side, + * with full horizontal coverage, `.opposite_coverage` one the actual + * cell (outside of the raster) will contribute to the first column's + * `.cell_coverage` */ + cell = (size_t)cellY * raster->width; + raster->cells[cell].opposite_coverage += y - prevY; + raster->cells[cell].cell_coverage += y - prevY; + + } else if ((size_t)cellX >= raster->width) { + /* If outside of the raster, on the right side, add to the last + * columns contributions to the next column, so that the ink level + * balances out to zero */ + cell = (size_t)cellY * raster->width + (raster->width - 1); + raster->cells[cell].opposite_coverage += y - prevY; + + } else { + /* If inside the raster, just draw the line */ + cell = (size_t)cellY * raster->width + (size_t)cellX; + raster->cells[cell].opposite_coverage += y - prevY; + raster->cells[cell].cell_coverage += (y - prevY) * fabs(fmax(ceil(x), ceil(prevX)) - (x + prevX) / 2.0); + } + } +} + + +#else + + +int +main(void) +{ + return 0; /* TODO add test */ +} + + +#endif diff --git a/rtgrpblib_draw_linear_bezier.c b/rtgrpblib_draw_linear_bezier.c index 5c83591..ba8dc48 100644 --- a/rtgrpblib_draw_linear_bezier.c +++ b/rtgrpblib_draw_linear_bezier.c @@ -9,6 +9,11 @@ rtgrpblib_draw_linear_bezier(RASTER *restrict raster, double x1, double y1, doub double w, h, dx, dy, x, y; int xdir, ydir; + if (raster->draftness <= 0) { + draw_linear_bezier_reference(raster, x1, y1, x2, y2); + return; + } + dx = x2 - x1; dy = y2 - y1; xdir = SIGNUM(dx); |