diff --git a/src/lolwut.c b/src/lolwut.c index 6047da29..a6fa8683 100644 --- a/src/lolwut.c +++ b/src/lolwut.c @@ -33,16 +33,18 @@ * each new version of Redis. */ +#include "server.h" + /* This function represents our canvas. Drawing functions will take a pointer * to a canvas to write to it. Later the canvas can be rendered to a string * suitable to be printed on the screen, using unicode Braille characters. */ -struct lwCanvas { +typedef struct lwCanvas { int width; int height; char *pixels; -}; +} lwCanvas; -/* Translate a group of 8 pixels (2x8 vertical rectangle) to the corresponding +/* Translate a group of 8 pixels (2x4 vertical rectangle) to the corresponding * braille character. The byte should correspond to the pixels arranged as * follows, where 0 is the least significant bit, and 7 the most significant * bit: @@ -56,14 +58,83 @@ struct lwCanvas { * pointed by 'output'. */ #include -void lwEmitPixelsGroup(int byte, char *output) { +void lwTranslatePixelsGroup(int byte, char *output) { int code = 0x2800 + byte; /* Convert to unicode. This is in the U0800-UFFFF range, so we need to * emit it like this in three bytes: * 1110xxxx 10xxxxxx 10xxxxxx. */ - output[1] = 0xE0 | (code >> 12); /* 1110-xxxx */ - output[2] = 0x80 | ((code >> 6) & 0x3F); /* 10-xxxxxx */ - output[3] = 0x80 | (code & 0x3F); /* 10-xxxxxx */ + output[0] = 0xE0 | (code >> 12); /* 1110-xxxx */ + output[1] = 0x80 | ((code >> 6) & 0x3F); /* 10-xxxxxx */ + output[2] = 0x80 | (code & 0x3F); /* 10-xxxxxx */ } +/* Allocate and return a new canvas of the specified size. */ +lwCanvas *lwCreateCanvas(int width, int height) { + lwCanvas *canvas = zmalloc(sizeof(*canvas)); + canvas->width = width; + canvas->height = height; + canvas->pixels = zmalloc(width*height); + memset(canvas->pixels,0,width*height); + return canvas; +} +/* Free the canvas created by lwCreateCanvas(). */ +void lwFreeCanvas(lwCanvas *canvas) { + zfree(canvas->pixels); + zfree(canvas); +} + +/* Set a pixel to the specified color. Color is 0 or 1, where zero means no + * dot will be displyed, and 1 means dot will be displayed. + * Coordinates are arranged so that left-top corner is 0,0. You can write + * out of the size of the canvas without issues. */ +void lwPutPixel(lwCanvas *canvas, int x, int y, int color) { + if (x < 0 || x >= canvas->width || + y < 0 || y >= canvas->height) return; + canvas->pixels[x+y*canvas->width] = color; +} + +/* Return the value of the specified pixel on the canvas. */ +int lwGetPixel(lwCanvas *canvas, int x, int y) { + if (x < 0 || x >= canvas->width || + y < 0 || y >= canvas->height) return 0; + return canvas->pixels[x+y*canvas->width]; +} + +/* Converts the canvas to an SDS string representing the UTF8 characters to + * print to the terminal in order to obtain a graphical representaiton of the + * logical canvas. The actual returned string will require a terminal that is + * width/2 large and height/4 tall in order to hold the whole image without + * overflowing or scrolling, since each Barille character is 2x4. */ +sds lwRenderCanvas(lwCanvas *canvas) { + sds text = sdsempty(); + for (int y = 0; y < canvas->height; y += 4) { + for (int x = 0; x < canvas->width; x += 2) { + /* We need to emit groups of 8 bits according to a specific + * arrangement. See lwTranslatePixelsGroup() for more info. */ + int byte = 0; + if (lwGetPixel(canvas,x,y)) byte |= (1<<0); + if (lwGetPixel(canvas,x,y+1)) byte |= (1<<1); + if (lwGetPixel(canvas,x,y+2)) byte |= (1<<2); + if (lwGetPixel(canvas,x+1,y)) byte |= (1<<3); + if (lwGetPixel(canvas,x+1,y+1)) byte |= (1<<4); + if (lwGetPixel(canvas,x+1,y+2)) byte |= (1<<5); + if (lwGetPixel(canvas,x,y+3)) byte |= (1<<6); + if (lwGetPixel(canvas,x+1,y+3)) byte |= (1<<7); + char unicode[3]; + lwTranslatePixelsGroup(byte,unicode); + text = sdscatlen(text,unicode,3); + } + if (y != canvas->height-1) text = sdscatlen(text,"\n",1); + } + return text; +} + +int main(void) { + lwCanvas *c = lwCreateCanvas(80,80); + for (int i = 0; i < 40; i++) { + lwPutPixel(c,i,i,1); + } + sds rendered = lwRenderCanvas(c); + printf("%s\n", rendered); +}