keyboard.c (11590B)
1/* 2 * keyboard.c 3 * written by Holmes Futrell 4 * use however you want 5 */ 6 7#import "SDL.h" 8#import "common.h" 9 10#define GLYPH_SIZE_IMAGE 16 /* size of glyphs (characters) in the bitmap font file */ 11#define GLYPH_SIZE_SCREEN 32 /* size of glyphs (characters) as shown on the screen */ 12 13static SDL_Texture *texture; /* texture where we'll hold our font */ 14 15/* function declarations */ 16void cleanup(void); 17void drawBlank(int x, int y); 18 19static SDL_Renderer *renderer; 20static int numChars = 0; /* number of characters we've typed so far */ 21static SDL_bool lastCharWasColon = 0; /* we use this to detect sequences such as :) */ 22static SDL_Color bg_color = { 50, 50, 100, 255 }; /* color of background */ 23 24/* this structure maps a scancode to an index in our bitmap font. 25 it also contains data about under which modifiers the mapping is valid 26 (for example, we don't want shift + 1 to produce the character '1', 27 but rather the character '!') 28*/ 29typedef struct 30{ 31 SDL_Scancode scancode; /* scancode of the key we want to map */ 32 int allow_no_mod; /* is the map valid if the key has no modifiers? */ 33 SDL_Keymod mod; /* what modifiers are allowed for the mapping */ 34 int index; /* what index in the font does the scancode map to */ 35} fontMapping; 36 37#define TABLE_SIZE 51 /* size of our table which maps keys and modifiers to font indices */ 38 39/* Below is the table that defines the mapping between scancodes and modifiers to indices in the 40 bitmap font. As an example, then line '{ SDL_SCANCODE_A, 1, KMOD_SHIFT, 33 }' means, map 41 the key A (which has scancode SDL_SCANCODE_A) to index 33 in the font (which is a picture of an A), 42 The '1' means that the mapping is valid even if there are no modifiers, and KMOD_SHIFT means the 43 mapping is also valid if the user is holding shift. 44*/ 45fontMapping map[TABLE_SIZE] = { 46 47 {SDL_SCANCODE_A, 1, KMOD_SHIFT, 33}, /* A */ 48 {SDL_SCANCODE_B, 1, KMOD_SHIFT, 34}, /* B */ 49 {SDL_SCANCODE_C, 1, KMOD_SHIFT, 35}, /* C */ 50 {SDL_SCANCODE_D, 1, KMOD_SHIFT, 36}, /* D */ 51 {SDL_SCANCODE_E, 1, KMOD_SHIFT, 37}, /* E */ 52 {SDL_SCANCODE_F, 1, KMOD_SHIFT, 38}, /* F */ 53 {SDL_SCANCODE_G, 1, KMOD_SHIFT, 39}, /* G */ 54 {SDL_SCANCODE_H, 1, KMOD_SHIFT, 40}, /* H */ 55 {SDL_SCANCODE_I, 1, KMOD_SHIFT, 41}, /* I */ 56 {SDL_SCANCODE_J, 1, KMOD_SHIFT, 42}, /* J */ 57 {SDL_SCANCODE_K, 1, KMOD_SHIFT, 43}, /* K */ 58 {SDL_SCANCODE_L, 1, KMOD_SHIFT, 44}, /* L */ 59 {SDL_SCANCODE_M, 1, KMOD_SHIFT, 45}, /* M */ 60 {SDL_SCANCODE_N, 1, KMOD_SHIFT, 46}, /* N */ 61 {SDL_SCANCODE_O, 1, KMOD_SHIFT, 47}, /* O */ 62 {SDL_SCANCODE_P, 1, KMOD_SHIFT, 48}, /* P */ 63 {SDL_SCANCODE_Q, 1, KMOD_SHIFT, 49}, /* Q */ 64 {SDL_SCANCODE_R, 1, KMOD_SHIFT, 50}, /* R */ 65 {SDL_SCANCODE_S, 1, KMOD_SHIFT, 51}, /* S */ 66 {SDL_SCANCODE_T, 1, KMOD_SHIFT, 52}, /* T */ 67 {SDL_SCANCODE_U, 1, KMOD_SHIFT, 53}, /* U */ 68 {SDL_SCANCODE_V, 1, KMOD_SHIFT, 54}, /* V */ 69 {SDL_SCANCODE_W, 1, KMOD_SHIFT, 55}, /* W */ 70 {SDL_SCANCODE_X, 1, KMOD_SHIFT, 56}, /* X */ 71 {SDL_SCANCODE_Y, 1, KMOD_SHIFT, 57}, /* Y */ 72 {SDL_SCANCODE_Z, 1, KMOD_SHIFT, 58}, /* Z */ 73 {SDL_SCANCODE_0, 1, 0, 16}, /* 0 */ 74 {SDL_SCANCODE_1, 1, 0, 17}, /* 1 */ 75 {SDL_SCANCODE_2, 1, 0, 18}, /* 2 */ 76 {SDL_SCANCODE_3, 1, 0, 19}, /* 3 */ 77 {SDL_SCANCODE_4, 1, 0, 20}, /* 4 */ 78 {SDL_SCANCODE_5, 1, 0, 21}, /* 5 */ 79 {SDL_SCANCODE_6, 1, 0, 22}, /* 6 */ 80 {SDL_SCANCODE_7, 1, 0, 23}, /* 7 */ 81 {SDL_SCANCODE_8, 1, 0, 24}, /* 8 */ 82 {SDL_SCANCODE_9, 1, 0, 25}, /* 9 */ 83 {SDL_SCANCODE_SPACE, 1, 0, 0}, /* ' ' */ 84 {SDL_SCANCODE_1, 0, KMOD_SHIFT, 1}, /* ! */ 85 {SDL_SCANCODE_SLASH, 0, KMOD_SHIFT, 31}, /* ? */ 86 {SDL_SCANCODE_SLASH, 1, 0, 15}, /* / */ 87 {SDL_SCANCODE_COMMA, 1, 0, 12}, /* , */ 88 {SDL_SCANCODE_SEMICOLON, 1, 0, 27}, /* ; */ 89 {SDL_SCANCODE_SEMICOLON, 0, KMOD_SHIFT, 26}, /* : */ 90 {SDL_SCANCODE_PERIOD, 1, 0, 14}, /* . */ 91 {SDL_SCANCODE_MINUS, 1, 0, 13}, /* - */ 92 {SDL_SCANCODE_EQUALS, 0, KMOD_SHIFT, 11}, /* = */ 93 {SDL_SCANCODE_APOSTROPHE, 1, 0, 7}, /* ' */ 94 {SDL_SCANCODE_APOSTROPHE, 0, KMOD_SHIFT, 2}, /* " */ 95 {SDL_SCANCODE_5, 0, KMOD_SHIFT, 5}, /* % */ 96 97}; 98 99/* 100 This function maps an SDL_KeySym to an index in the bitmap font. 101 It does so by scanning through the font mapping table one entry 102 at a time. 103 104 If a match is found (scancode and allowed modifiers), the proper 105 index is returned. 106 107 If there is no entry for the key, -1 is returned 108*/ 109int 110keyToIndex(SDL_Keysym key) 111{ 112 int i, index = -1; 113 for (i = 0; i < TABLE_SIZE; i++) { 114 fontMapping compare = map[i]; 115 if (key.scancode == compare.scancode) { 116 /* if this entry is valid with no key mod and we have no keymod, or if 117 the key's modifiers are allowed modifiers for that mapping */ 118 if ((compare.allow_no_mod && key.mod == 0) 119 || (key.mod & compare.mod)) { 120 index = compare.index; 121 break; 122 } 123 } 124 } 125 return index; 126} 127 128/* 129 This function returns and x,y position for a given character number. 130 It is used for positioning each character of text 131*/ 132void 133getPositionForCharNumber(int n, int *x, int *y) 134{ 135 int x_padding = 16; /* padding space on left and right side of screen */ 136 int y_padding = 32; /* padding space at top of screen */ 137 /* figure out the number of characters that can fit horizontally across the screen */ 138 int max_x_chars = (SCREEN_WIDTH - 2 * x_padding) / GLYPH_SIZE_SCREEN; 139 int line_separation = 5; /* pixels between each line */ 140 *x = (n % max_x_chars) * GLYPH_SIZE_SCREEN + x_padding; 141 *y = (n / max_x_chars) * (GLYPH_SIZE_SCREEN + line_separation) + 142 y_padding; 143} 144 145void 146drawIndex(int index) 147{ 148 int x, y; 149 getPositionForCharNumber(numChars, &x, &y); 150 SDL_Rect srcRect = 151 { GLYPH_SIZE_IMAGE * index, 0, GLYPH_SIZE_IMAGE, GLYPH_SIZE_IMAGE }; 152 SDL_Rect dstRect = { x, y, GLYPH_SIZE_SCREEN, GLYPH_SIZE_SCREEN }; 153 drawBlank(x, y); 154 SDL_RenderCopy(renderer, texture, &srcRect, &dstRect); 155} 156 157/* draws the cursor icon at the current end position of the text */ 158void 159drawCursor(void) 160{ 161 drawIndex(29); /* cursor is at index 29 in the bitmap font */ 162} 163 164/* paints over a glyph sized region with the background color 165 in effect it erases the area 166*/ 167void 168drawBlank(int x, int y) 169{ 170 SDL_Rect rect = { x, y, GLYPH_SIZE_SCREEN, GLYPH_SIZE_SCREEN }; 171 SDL_SetRenderDrawColor(renderer, bg_color.r, bg_color.g, bg_color.b, bg_color.a); 172 SDL_RenderFillRect(renderer, &rect); 173} 174 175/* moves backwards one character, erasing the last one put down */ 176void 177backspace(void) 178{ 179 int x, y; 180 if (numChars > 0) { 181 getPositionForCharNumber(numChars, &x, &y); 182 drawBlank(x, y); 183 numChars--; 184 getPositionForCharNumber(numChars, &x, &y); 185 drawBlank(x, y); 186 drawCursor(); 187 } 188} 189 190/* this function loads our font into an SDL_Texture and returns the SDL_Texture */ 191SDL_Texture* 192loadFont(void) 193{ 194 195 SDL_Surface *surface = SDL_LoadBMP("kromasky_16x16.bmp"); 196 197 if (!surface) { 198 printf("Error loading bitmap: %s\n", SDL_GetError()); 199 return 0; 200 } else { 201 /* set the transparent color for the bitmap font (hot pink) */ 202 SDL_SetColorKey(surface, 1, SDL_MapRGB(surface->format, 238, 0, 252)); 203 /* now we convert the surface to our desired pixel format */ 204 int format = SDL_PIXELFORMAT_ABGR8888; /* desired texture format */ 205 Uint32 Rmask, Gmask, Bmask, Amask; /* masks for desired format */ 206 int bpp; /* bits per pixel for desired format */ 207 SDL_PixelFormatEnumToMasks(format, &bpp, &Rmask, &Gmask, &Bmask, 208 &Amask); 209 SDL_Surface *converted = 210 SDL_CreateRGBSurface(0, surface->w, surface->h, bpp, Rmask, Gmask, 211 Bmask, Amask); 212 SDL_BlitSurface(surface, NULL, converted, NULL); 213 /* create our texture */ 214 texture = 215 SDL_CreateTextureFromSurface(renderer, converted); 216 if (texture == 0) { 217 printf("texture creation failed: %s\n", SDL_GetError()); 218 } else { 219 /* set blend mode for our texture */ 220 SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND); 221 } 222 SDL_FreeSurface(surface); 223 SDL_FreeSurface(converted); 224 return texture; 225 } 226} 227 228int 229main(int argc, char *argv[]) 230{ 231 232 int index; /* index of last key we pushed in the bitmap font */ 233 SDL_Window *window; 234 SDL_Event event; /* last event received */ 235 SDL_Keymod mod; /* key modifiers of last key we pushed */ 236 SDL_Scancode scancode; /* scancode of last key we pushed */ 237 238 if (SDL_Init(SDL_INIT_VIDEO) < 0) { 239 printf("Error initializing SDL: %s", SDL_GetError()); 240 } 241 /* create window */ 242 window = SDL_CreateWindow("iPhone keyboard test", 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, 0); 243 /* create renderer */ 244 renderer = SDL_CreateRenderer(window, -1, 0); 245 246 /* load up our font */ 247 loadFont(); 248 249 /* draw the background, we'll just paint over it */ 250 SDL_SetRenderDrawColor(renderer, bg_color.r, bg_color.g, bg_color.b, bg_color.a); 251 SDL_RenderFillRect(renderer, NULL); 252 SDL_RenderPresent(renderer); 253 254 int done = 0; 255 /* loop till we get SDL_Quit */ 256 while (SDL_WaitEvent(&event)) { 257 switch (event.type) { 258 case SDL_QUIT: 259 done = 1; 260 break; 261 case SDL_KEYDOWN: 262 index = keyToIndex(event.key.keysym); 263 scancode = event.key.keysym.scancode; 264 mod = event.key.keysym.mod; 265 if (scancode == SDL_SCANCODE_DELETE) { 266 /* if user hit delete, delete the last character */ 267 backspace(); 268 lastCharWasColon = 0; 269 } else if (lastCharWasColon && scancode == SDL_SCANCODE_0 270 && (mod & KMOD_SHIFT)) { 271 /* if our last key was a colon and this one is a close paren, the make a hoppy face */ 272 backspace(); 273 drawIndex(32); /* index for happy face */ 274 numChars++; 275 drawCursor(); 276 lastCharWasColon = 0; 277 } else if (index != -1) { 278 /* if we aren't doing a happy face, then just draw the normal character */ 279 drawIndex(index); 280 numChars++; 281 drawCursor(); 282 lastCharWasColon = 283 (event.key.keysym.scancode == SDL_SCANCODE_SEMICOLON 284 && (event.key.keysym.mod & KMOD_SHIFT)); 285 } 286 /* check if the key was a colon */ 287 /* draw our updates to the screen */ 288 SDL_RenderPresent(renderer); 289 break; 290 case SDL_MOUSEBUTTONUP: 291 /* mouse up toggles onscreen keyboard visibility */ 292 if (SDL_IsTextInputActive()) { 293 SDL_StopTextInput(); 294 } else { 295 SDL_StartTextInput(); 296 } 297 break; 298 } 299 } 300 cleanup(); 301 return 0; 302} 303 304/* clean up after ourselves like a good kiddy */ 305void 306cleanup(void) 307{ 308 SDL_DestroyTexture(texture); 309 SDL_Quit(); 310}