diff options
Diffstat (limited to 'memview.c')
| -rw-r--r-- | memview.c | 26 |
1 files changed, 25 insertions, 1 deletions
@@ -39,7 +39,8 @@ uintptr_t to_addr(int x, int y) { memcpy(&ux, &x, sizeof(unsigned int)); memcpy(&uy, &y, sizeof(unsigned int)); uintptr_t page = zorder(ux / PAGE_WIDTH, uy / PAGE_HEIGHT); - int offset = x % PAGE_WIDTH + y % PAGE_HEIGHT * PAGE_WIDTH; + int offset = + x % PAGE_WIDTH / CHAR_BIT + y % PAGE_HEIGHT * PAGE_WIDTH / CHAR_BIT; return page * PAGE_SIZE + offset; } @@ -135,3 +136,26 @@ bool render_pages(struct viewer *v, } return present; } + +static void write_bit(int fd, int x, int y, bool bit) { + uintptr_t addr = to_addr(x, y); + int bit_offs = x % CHAR_BIT; + uint8_t byte; + if (read_mem(fd, addr, &byte, 1) == -1) return; + byte = (byte & ~(1 << bit_offs)) | (bit << bit_offs); + write_mem(fd, addr, &byte, 1); +} + +void pencil(struct viewer *v, + double x1, double y1, double x2, double y2, bool bit) { + double dx = (x2 - x1); + double dy = (y2 - y1); + int step = abs(dx) >= abs(dy) ? abs(dx) : abs(dy); + dx = dx / step; dy = dy / step; + double x = x1; double y = y1; + for (int i = 0; i <= step; i++) { + write_bit(v->fd, x, y, bit); + x = x + dx; + y = y + dy; + } +} |