diff options
Diffstat (limited to 'include/buchstabensuppe.h')
| -rw-r--r-- | include/buchstabensuppe.h | 250 |
1 files changed, 246 insertions, 4 deletions
diff --git a/include/buchstabensuppe.h b/include/buchstabensuppe.h index 461d96f..d1f8a62 100644 --- a/include/buchstabensuppe.h +++ b/include/buchstabensuppe.h @@ -4,12 +4,10 @@ #ifndef BUCHSTABENSUPPE_H #define BUCHSTABENSUPPE_H -#include <buchstabensuppe/bitmap.h> - #include <stdbool.h> #include <stddef.h> - -// buffers +#include <stdint.h> +#include <sys/socket.h> /* sockaddr */ /*! * @name UTF-32 Buffer API @@ -34,6 +32,250 @@ bs_utf32_buffer_t bs_decode_utf8(const char *, size_t); //! @} /*! + * @name Grayscale Bitmap API + * @{ + */ + +/*! + * @brief 8-bit bitmap + * + * bs_bitmap_t wraps a `unsigned char` buffer + * representing a bitmap of a certain width + * and height. The pixels are written into + * the buffer row by row. This means the + * index of a pixel is computed like this: + * `y * width + x`. + */ +typedef struct bs_bitmap { + unsigned char *bs_bitmap; //!< Dynamically allocated bitmap buffer + + int bs_bitmap_height; //!< Height of the bitmap + int bs_bitmap_width; //!< Width of the bitmap + // TODO make unsigned +} bs_bitmap_t; + +/*! + * @brief Create a new bitmap + * + * Creates a new bitmap with the given width and height. + * The allocated bitmap is then initialized to hold the + * value `initial` for every pixel. + * + * The caller is responsible for freeing the returned bitmap. + */ +bs_bitmap_t bs_bitmap_new(int width, int height, unsigned char inital); + +/*! + * @brief Free a bitmap's buffer + * + * Frees the buffer allocated for the given bitmap and + * updates its dimensions to zero width and height, so + * future operations won't crash. Note that this does + * _not_ free the bitmap structure itself as it is not + * intended to be dynamically allocated. + */ +void bs_bitmap_free(bs_bitmap_t *bitmap); + +/*! + * @brief Increase the size of a bitmap + * + * Resizes the bitmap to a new size, but will only increase + * its size. The newly allocated space is then intialized + * with the given value. + */ +bool bs_bitmap_extend(bs_bitmap_t *bitmap, int new_width, + int new_height, unsigned char initial_value); + +/*! + * @brief Set a pixel value + * + * Sets the pixel at the specified location to the given value + * or does nothing if the location is out of bounds. + */ +void bs_bitmap_set(bs_bitmap_t bitmap, int x, int y, unsigned char value); + +/*! + * @brief Get a pixel value + * + * Gets the value at the specified location. If the location + * is out of bounds it returns `def` and sets `errno` to `EINVAL`. + */ +unsigned char bs_bitmap_get(bs_bitmap_t bitmap, int x, int y, unsigned char def); + +/*! + * @brief Copy a bitmap into another one + * + * Copies the source bitmap into the destination one with the + * given offset. Any overflow is cut off, offsets may be + * negative as well. + */ +void bs_bitmap_copy(bs_bitmap_t destination, int offset_x, + int offset_y, bs_bitmap_t source); + +/*! + * @brief Print a representation of a bitmap to stdout + * + * Uses the unicode block character to render a representation + * of the bitmap. If `binary_image` is false, the image is + * considered as a grayscale image and all values greater than + * 0x80 are rendered as “white” pixels, all below as “black” + * pixels. Else 1 is “white”, 0 is “black”. + */ +void bs_bitmap_print(bs_bitmap_t bitmap, bool binary_image); + +/*! + * @brief Map a bitmap + * + * Calls the provided function on every pixel of the bitmap + * and sets it to the returned value. + */ +void bs_bitmap_map(bs_bitmap_t bitmap, unsigned char (*fun)(unsigned char)); + +/*! + * @brief Invert a binary pixel + * + * To be used with bs_bitmap_map(). + */ +unsigned char bs_pixel_invert_binary(unsigned char); + +/*! + * @brief Invert a grayscale pixel + * + * To be used with bs_bitmap_map(). + */ +unsigned char bs_pixel_invert_grayscale(unsigned char); + +/*! + * @brief Convert a grayscale pixel to binary + * + * To be used with bs_bitmap_map(). + */ +unsigned char bs_pixel_to_binary(unsigned char); + +/*! + * @brief convert a binary pixel to grayscale + * + * To be used with bs_bitmap_map(). + */ +unsigned char bs_pixel_to_grayscale(unsigned char); + +//! @} + +/*! + * @name Bitmap Views + * @{ + */ + +/*! + * @brief Bitmap subset + * + * A view represents a cropped bitmap in + * a cheap manner similar to a string slice. + */ +typedef struct bs_bm_view { + bs_bitmap_t bs_view_bitmap; + int bs_view_offset_x; + int bs_view_offset_y; + int bs_view_width; + int bs_view_height; +} bs_view_t; + +/* + * @brief Compact a binary bitmap + * + * This converts a binary bitmap into a more compact + * representation which every byte stores 8 pixels + * instead of just 1. The highest bit represents the + * pixel that comes first in the bitmap. + * + * The resulting format is precisely what the + * [Flidpot UDP protocol](https://wiki.openlab-augsburg.de/Flipdots#per-udp-schnittstelle) + * requires. + * + * `view` describes the bitmap to be used and the area + * of it. `size` will hold the length of the returned array. + * + * If the `view` contains areas which are not covered by its + * bitmap, these pixels are treated as if they had the value + * `def`. + * + * On error `NULL` is returned and `size` is 0. The allocated + * memory must be freed by the caller. + */ +uint8_t *bs_view_bitarray(bs_view_t view, size_t *size, unsigned char def); + +/*! + * @brief Axis description + * + * Describes which direction to perform a movement in for + * bs_scroll_next_view() and bs_page_next_view(). + */ +enum bs_dimension { + BS_DIMENSION_X, //!< X Axis + BS_DIMENSION_Y, //!< Y Axis +}; + +/*! + * @brief Calculates next view for a one dimensional scroll through a bitmap. + * + * Advance a bitmap view by `step` in a given dimension. Will return `true` + * as soon as the bitmap is out of view and wrap around, i. e. sets the offset + * to `-len`. This is intended to provide the view for the next frame to be + * rendered to a (flipdot) display. + * + * The given view is expected to be fully intialized and `bs_view_width` and + * `bs_view_height` to be equal to the dimensions of the target screen. Also + * the first view position must be set by the caller. + * + * @param view bitmap view to alter + * @param step step to advance by + * @param dim dimension to advance in + * + * @return true if the bitmap has come out of view, + * i. e. the scrolling motion is finished + */ +bool bs_scroll_next_view(bs_view_t *view, int step, enum bs_dimension dim); + +/*! + * @brief Calculates next view for one dimensional paging through a bitmap. + * + * This is similar to bs_scroll_next_view(), but the scroll step is the target + * display's width or height and the picture is never scrolled out of view. + * + * If the edge of the bitmap is in view, true is returned and the offset is + * set so the first page is in view. + * + * @param view bitmap view to alter + * @param step step to advance by + * @param dim dimension to advance in + * + * @return true if another page would mean the bitmap would come out of view + * i. e. all pages have been viewed + */ +bool bs_page_next_view(bs_view_t *view, int direction, enum bs_dimension dim); + +/*! + * @brief Render a bitmap view onto a flipdot display + * + * This function renders a view to a flipdot display compatible bitarray + * using bs_view_bitmap() and sends it to a display listening at the given + * address using a given socket. + * + * The viewed bitmap must be a binary bitmap for this to work properly. + * Zero is black, all values greater than zero are white. + * + * @param sockfd file descriptor of a `SOCK_DGRAM` socket + * @param addr address of the target flipdot display + * @param addrlen length of the address structure + * @param view bitmap view to render + * @param overflow_color value area outside of the picture should get (either 0 or 1) + */ +int bs_flipdot_render(int sockfd, struct sockaddr *addr, socklen_t addrlen, + bs_view_t view, unsigned char overflow_color); + +//! @} + +/*! * @name Font Rendering * @{ */ |