diff options
Diffstat (limited to 'framebuffer.c')
| -rw-r--r-- | framebuffer.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/framebuffer.c b/framebuffer.c new file mode 100644 index 0000000..29459ac --- /dev/null +++ b/framebuffer.c @@ -0,0 +1,183 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" + + +/** + * The psuedodevice pathname pattern used to access a framebuffer + */ +#ifndef FB_DEVICE_PATTERN +# define FB_DEVICE_PATTERN "/dev/fb%lu" +#endif + + +/** + * The number of elements to allocates to a buffer for a framebuffer device pathname + */ +#define FB_DEVICE_MAX_LEN (sizeof(FB_DEVICE_PATTERN) / sizeof(char) + 3 * sizeof(size_t)) + + + +/** + * Figure out how many framebuffers there are on the system + * + * @return The number of framebuffers on the system + */ +size_t +fb_count(void) +{ + char buf[FB_DEVICE_MAX_LEN]; + size_t count = 0; + + for (;; count++) { + sprintf(buf, FB_DEVICE_PATTERN, count); + if (access(buf, F_OK) < 0) + return count; + } +} + + +/** + * Open a framebuffer + * + * @param index The index of the framebuffer to open + * @param fb Framebuffer information to fill in + * @return Zero on success, -1 on error + */ +int +fb_open(size_t index, framebuffer_t *restrict fb) +{ + char buf[FB_DEVICE_MAX_LEN]; + struct fb_fix_screeninfo fix_info; + struct fb_var_screeninfo var_info; + int old_errno; + + fb->fd = -1; + fb->mem = MAP_FAILED; + + sprintf(buf, FB_DEVICE_PATTERN, index); + fb->fd = open(buf, O_RDWR); + if (fb->fd < 0) + goto fail; + + if (ioctl(fb->fd, (unsigned long int)FBIOGET_FSCREENINFO, &fix_info) || + ioctl(fb->fd, (unsigned long int)FBIOGET_VSCREENINFO, &var_info)) + goto fail; + + fb->mem = mmap(NULL, (size_t)(fix_info.smem_len), PROT_WRITE, MAP_SHARED, fb->fd, (off_t)0); + if (fb->mem == MAP_FAILED) + goto fail; + + fb->mem += var_info.xoffset * (var_info.bits_per_pixel / 8); + fb->mem += var_info.yoffset * fix_info.line_length; + + fb->width = var_info.xres; + fb->height = var_info.yres; + fb->bytes_per_pixel = var_info.bits_per_pixel / 8; + fb->line_length = fix_info.line_length; + + return 0; +fail: + old_errno = errno; + fb_close(fb); + errno = old_errno; + return -1; +} + + +/** + * Close a framebuffer + * + * @param fb The framebuffer information + */ +void +fb_close(framebuffer_t *restrict fb) +{ + if (fb->fd >= 0) { + close(fb->fd); + fb->fd = -1; + } +} + + +/** + * Construct an sRGB colour in 32-bit XRGB encoding to + * use when specifying colours + * + * @param red The red component from [0, 255] sRGB + * @param green The green component from [0, 255] sRGB + * @param blue The blue component from [0, 255] sRGB + * @return The colour as one 32-bit integer + */ +uint32_t +fb_colour(int red, int green, int blue) +{ + uint32_t rc = 0; + rc |= (uint32_t)red, rc <<= 8; + rc |= (uint32_t)green, rc <<= 8; + rc |= (uint32_t)blue; + return rc; +} + + +/** + * Print a filled in rectangle to a framebuffer + * + * @param fb The framebuffer + * @param colour The colour to use when drawing the rectangle + * @param x The starting pixel on the X axis for the rectangle + * @param y The starting pixel on the Y axis for the rectangle + * @param width The width of the rectangle, in pixels + * @param height The height of the rectangle, in pixels + */ +void +fb_fill_rectangle(framebuffer_t *restrict fb, uint32_t colour, uint32_t x, uint32_t y, uint32_t width, uint32_t height) +{ + int8_t *mem = fb->mem + y * fb->line_length; + size_t x1 = x * fb->bytes_per_pixel; + size_t x2 = (x + width) * fb->bytes_per_pixel; + size_t y2 = y + height; + size_t x_, y_; + for (y_ = y; y_ != y2; y_++, mem += fb->line_length) + for (x_ = x1; x_ != x2; x_ += fb->bytes_per_pixel) + *(uint32_t *)&mem[x_] = colour; +} + + +/** + * Draw a horizontal line segment on a framebuffer + * + * @param fb The framebuffer + * @param colour The colour to use when drawing the rectangle + * @param x The starting pixel on the X axis for the line segment + * @param y The starting pixel on the Y axis for the line segment + * @param length The length of the line segment, in pixels + */ +void fb_draw_horizontal_line(framebuffer_t *restrict fb, uint32_t colour, uint32_t x, uint32_t y, uint32_t length) +{ + int8_t *mem = fb->mem + y * fb->line_length; + size_t x1 = x * fb->bytes_per_pixel; + size_t x2 = (x + length) * fb->bytes_per_pixel; + size_t x_; + for (x_ = x1; x_ != x2; x_ += fb->bytes_per_pixel) + *(uint32_t *)&mem[x_] = colour; +} + + +/** + * Draw a vertical line segment on a framebuffer + * + * @param fb The framebuffer + * @param colour The colour to use when drawing the rectangle + * @param x The starting pixel on the X axis for the line segment + * @param y The starting pixel on the Y axis for the line segment + * @param length The length of the line segment, in pixels + */ +void fb_draw_vertical_line(framebuffer_t *restrict fb, uint32_t colour, uint32_t x, uint32_t y, uint32_t length) +{ + int8_t *mem = fb->mem + y * fb->line_length + x * fb->bytes_per_pixel; + size_t y2 = y + length; + size_t y_; + + for (y_ = y; y_ != y2; y_++, mem += fb->line_length) + *(uint32_t *)mem = colour; +} |