keyboard.c (11029B)
1 /* 2 * keyboard.c 3 * written by Holmes Futrell 4 * use however you want 5 */ 6 7 #include "SDL.h" 8 #include "common.h" 9 10 #define TEST_INPUT_RECT 11 12 #define GLYPH_SIZE_IMAGE 16 /* size of glyphs (characters) in the bitmap font file */ 13 #define GLYPH_SIZE_SCREEN 32 /* size of glyphs (characters) as shown on the screen */ 14 15 #define MAX_CHARS 1024 16 17 static SDL_Texture *texture; /* texture where we'll hold our font */ 18 19 static SDL_Renderer *renderer; 20 static int numChars = 0; /* number of characters we've typed so far */ 21 static SDL_Color bg_color = { 50, 50, 100, 255 }; /* color of background */ 22 23 static int glyphs[MAX_CHARS]; 24 25 /* this structure maps a scancode to an index in our bitmap font. 26 it also contains data about under which modifiers the mapping is valid 27 (for example, we don't want shift + 1 to produce the character '1', 28 but rather the character '!') 29 */ 30 typedef struct 31 { 32 SDL_Scancode scancode; /* scancode of the key we want to map */ 33 int allow_no_mod; /* is the map valid if the key has no modifiers? */ 34 SDL_Keymod mod; /* what modifiers are allowed for the mapping */ 35 int index; /* what index in the font does the scancode map to */ 36 } fontMapping; 37 38 #define TABLE_SIZE 51 /* size of our table which maps keys and modifiers to font indices */ 39 40 /* Below is the table that defines the mapping between scancodes and modifiers to indices in the 41 bitmap font. As an example, then line '{ SDL_SCANCODE_A, 1, KMOD_SHIFT, 33 }' means, map 42 the key A (which has scancode SDL_SCANCODE_A) to index 33 in the font (which is a picture of an A), 43 The '1' means that the mapping is valid even if there are no modifiers, and KMOD_SHIFT means the 44 mapping is also valid if the user is holding shift. 45 */ 46 fontMapping map[TABLE_SIZE] = { 47 48 {SDL_SCANCODE_A, 1, KMOD_SHIFT, 33}, /* A */ 49 {SDL_SCANCODE_B, 1, KMOD_SHIFT, 34}, /* B */ 50 {SDL_SCANCODE_C, 1, KMOD_SHIFT, 35}, /* C */ 51 {SDL_SCANCODE_D, 1, KMOD_SHIFT, 36}, /* D */ 52 {SDL_SCANCODE_E, 1, KMOD_SHIFT, 37}, /* E */ 53 {SDL_SCANCODE_F, 1, KMOD_SHIFT, 38}, /* F */ 54 {SDL_SCANCODE_G, 1, KMOD_SHIFT, 39}, /* G */ 55 {SDL_SCANCODE_H, 1, KMOD_SHIFT, 40}, /* H */ 56 {SDL_SCANCODE_I, 1, KMOD_SHIFT, 41}, /* I */ 57 {SDL_SCANCODE_J, 1, KMOD_SHIFT, 42}, /* J */ 58 {SDL_SCANCODE_K, 1, KMOD_SHIFT, 43}, /* K */ 59 {SDL_SCANCODE_L, 1, KMOD_SHIFT, 44}, /* L */ 60 {SDL_SCANCODE_M, 1, KMOD_SHIFT, 45}, /* M */ 61 {SDL_SCANCODE_N, 1, KMOD_SHIFT, 46}, /* N */ 62 {SDL_SCANCODE_O, 1, KMOD_SHIFT, 47}, /* O */ 63 {SDL_SCANCODE_P, 1, KMOD_SHIFT, 48}, /* P */ 64 {SDL_SCANCODE_Q, 1, KMOD_SHIFT, 49}, /* Q */ 65 {SDL_SCANCODE_R, 1, KMOD_SHIFT, 50}, /* R */ 66 {SDL_SCANCODE_S, 1, KMOD_SHIFT, 51}, /* S */ 67 {SDL_SCANCODE_T, 1, KMOD_SHIFT, 52}, /* T */ 68 {SDL_SCANCODE_U, 1, KMOD_SHIFT, 53}, /* U */ 69 {SDL_SCANCODE_V, 1, KMOD_SHIFT, 54}, /* V */ 70 {SDL_SCANCODE_W, 1, KMOD_SHIFT, 55}, /* W */ 71 {SDL_SCANCODE_X, 1, KMOD_SHIFT, 56}, /* X */ 72 {SDL_SCANCODE_Y, 1, KMOD_SHIFT, 57}, /* Y */ 73 {SDL_SCANCODE_Z, 1, KMOD_SHIFT, 58}, /* Z */ 74 {SDL_SCANCODE_0, 1, 0, 16}, /* 0 */ 75 {SDL_SCANCODE_1, 1, 0, 17}, /* 1 */ 76 {SDL_SCANCODE_2, 1, 0, 18}, /* 2 */ 77 {SDL_SCANCODE_3, 1, 0, 19}, /* 3 */ 78 {SDL_SCANCODE_4, 1, 0, 20}, /* 4 */ 79 {SDL_SCANCODE_5, 1, 0, 21}, /* 5 */ 80 {SDL_SCANCODE_6, 1, 0, 22}, /* 6 */ 81 {SDL_SCANCODE_7, 1, 0, 23}, /* 7 */ 82 {SDL_SCANCODE_8, 1, 0, 24}, /* 8 */ 83 {SDL_SCANCODE_9, 1, 0, 25}, /* 9 */ 84 {SDL_SCANCODE_SPACE, 1, 0, 0}, /* ' ' */ 85 {SDL_SCANCODE_1, 0, KMOD_SHIFT, 1}, /* ! */ 86 {SDL_SCANCODE_SLASH, 0, KMOD_SHIFT, 31}, /* ? */ 87 {SDL_SCANCODE_SLASH, 1, 0, 15}, /* / */ 88 {SDL_SCANCODE_COMMA, 1, 0, 12}, /* , */ 89 {SDL_SCANCODE_SEMICOLON, 1, 0, 27}, /* ; */ 90 {SDL_SCANCODE_SEMICOLON, 0, KMOD_SHIFT, 26}, /* : */ 91 {SDL_SCANCODE_PERIOD, 1, 0, 14}, /* . */ 92 {SDL_SCANCODE_MINUS, 1, 0, 13}, /* - */ 93 {SDL_SCANCODE_EQUALS, 0, KMOD_SHIFT, 11}, /* = */ 94 {SDL_SCANCODE_APOSTROPHE, 1, 0, 7}, /* ' */ 95 {SDL_SCANCODE_APOSTROPHE, 0, KMOD_SHIFT, 2}, /* " */ 96 {SDL_SCANCODE_5, 0, KMOD_SHIFT, 5}, /* % */ 97 98 }; 99 100 /* 101 This function maps an SDL_KeySym to an index in the bitmap font. 102 It does so by scanning through the font mapping table one entry 103 at a time. 104 105 If a match is found (scancode and allowed modifiers), the proper 106 index is returned. 107 108 If there is no entry for the key, -1 is returned 109 */ 110 int 111 keyToGlyphIndex(SDL_Keysym key) 112 { 113 int i, index = -1; 114 for (i = 0; i < TABLE_SIZE; i++) { 115 fontMapping compare = map[i]; 116 if (key.scancode == compare.scancode) { 117 /* if this entry is valid with no key mod and we have no keymod, or if 118 the key's modifiers are allowed modifiers for that mapping */ 119 if ((compare.allow_no_mod && key.mod == 0) 120 || (key.mod & compare.mod)) { 121 index = compare.index; 122 break; 123 } 124 } 125 } 126 return index; 127 } 128 129 /* 130 This function returns and x,y position for a given character number. 131 It is used for positioning each character of text 132 */ 133 void 134 getPositionForCharNumber(int n, int *x, int *y) 135 { 136 int renderW, renderH; 137 SDL_RenderGetLogicalSize(renderer, &renderW, &renderH); 138 139 int x_padding = 16; /* padding space on left and right side of screen */ 140 int y_padding = 32; /* padding space at top of screen */ 141 /* figure out the number of characters that can fit horizontally across the screen */ 142 int max_x_chars = (renderW - 2 * x_padding) / GLYPH_SIZE_SCREEN; 143 int line_separation = 5; /* pixels between each line */ 144 *x = (n % max_x_chars) * GLYPH_SIZE_SCREEN + x_padding; 145 #ifdef TEST_INPUT_RECT 146 *y = renderH - GLYPH_SIZE_SCREEN; 147 #else 148 *y = (n / max_x_chars) * (GLYPH_SIZE_SCREEN + line_separation) + y_padding; 149 #endif 150 } 151 152 void 153 drawGlyph(int glyph, int positionIndex) 154 { 155 int x, y; 156 getPositionForCharNumber(positionIndex, &x, &y); 157 SDL_Rect srcRect = { GLYPH_SIZE_IMAGE * glyph, 0, GLYPH_SIZE_IMAGE, GLYPH_SIZE_IMAGE }; 158 SDL_Rect dstRect = { x, y, GLYPH_SIZE_SCREEN, GLYPH_SIZE_SCREEN }; 159 SDL_RenderCopy(renderer, texture, &srcRect, &dstRect); 160 } 161 162 /* this function loads our font into an SDL_Texture and returns the SDL_Texture */ 163 SDL_Texture* 164 loadFont(void) 165 { 166 SDL_Surface *surface = SDL_LoadBMP("kromasky_16x16.bmp"); 167 168 if (!surface) { 169 printf("Error loading bitmap: %s\n", SDL_GetError()); 170 return 0; 171 } else { 172 /* set the transparent color for the bitmap font (hot pink) */ 173 SDL_SetColorKey(surface, 1, SDL_MapRGB(surface->format, 238, 0, 252)); 174 /* now we convert the surface to our desired pixel format */ 175 int format = SDL_PIXELFORMAT_ABGR8888; /* desired texture format */ 176 Uint32 Rmask, Gmask, Bmask, Amask; /* masks for desired format */ 177 int bpp; /* bits per pixel for desired format */ 178 SDL_PixelFormatEnumToMasks(format, &bpp, &Rmask, &Gmask, &Bmask, 179 &Amask); 180 SDL_Surface *converted = 181 SDL_CreateRGBSurface(0, surface->w, surface->h, bpp, Rmask, Gmask, 182 Bmask, Amask); 183 SDL_BlitSurface(surface, NULL, converted, NULL); 184 /* create our texture */ 185 texture = SDL_CreateTextureFromSurface(renderer, converted); 186 if (texture == 0) { 187 printf("texture creation failed: %s\n", SDL_GetError()); 188 } else { 189 /* set blend mode for our texture */ 190 SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND); 191 } 192 SDL_FreeSurface(surface); 193 SDL_FreeSurface(converted); 194 return texture; 195 } 196 } 197 198 void 199 draw() 200 { 201 SDL_SetRenderDrawColor(renderer, bg_color.r, bg_color.g, bg_color.b, bg_color.a); 202 SDL_RenderClear(renderer); 203 204 for (int i = 0; i < numChars; i++) { 205 drawGlyph(glyphs[i], i); 206 } 207 208 drawGlyph(29, numChars); /* cursor is at index 29 in the bitmap font */ 209 210 SDL_RenderPresent(renderer); 211 } 212 213 int 214 main(int argc, char *argv[]) 215 { 216 SDL_Window *window; 217 SDL_Event event; /* last event received */ 218 SDL_Scancode scancode; /* scancode of last key we pushed */ 219 int width; 220 int height; 221 int done; 222 SDL_Rect textrect; 223 224 if (SDL_Init(SDL_INIT_VIDEO) < 0) { 225 printf("Error initializing SDL: %s", SDL_GetError()); 226 } 227 /* create window */ 228 window = SDL_CreateWindow("iOS keyboard test", 0, 0, 0, 0, SDL_WINDOW_FULLSCREEN_DESKTOP | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI); 229 /* create renderer */ 230 renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_PRESENTVSYNC); 231 232 SDL_GetWindowSize(window, &width, &height); 233 SDL_RenderSetLogicalSize(renderer, width, height); 234 235 /* load up our font */ 236 loadFont(); 237 238 /* Show onscreen keyboard */ 239 #ifdef TEST_INPUT_RECT 240 textrect.x = 0; 241 textrect.y = height - GLYPH_SIZE_IMAGE; 242 textrect.w = width; 243 textrect.h = GLYPH_SIZE_IMAGE; 244 SDL_SetTextInputRect(&textrect); 245 #endif 246 SDL_StartTextInput(); 247 248 done = 0; 249 while (!done) { 250 while (SDL_PollEvent(&event)) { 251 switch (event.type) { 252 case SDL_QUIT: 253 done = 1; 254 break; 255 case SDL_WINDOWEVENT: 256 if (event.window.event == SDL_WINDOWEVENT_RESIZED) { 257 width = event.window.data1; 258 height = event.window.data2; 259 SDL_RenderSetLogicalSize(renderer, width, height); 260 #ifdef TEST_INPUT_RECT 261 textrect.x = 0; 262 textrect.y = height - GLYPH_SIZE_IMAGE; 263 textrect.w = width; 264 textrect.h = GLYPH_SIZE_IMAGE; 265 SDL_SetTextInputRect(&textrect); 266 #endif 267 } 268 break; 269 case SDL_KEYDOWN: 270 if (event.key.keysym.scancode == SDL_SCANCODE_BACKSPACE) { 271 if (numChars > 0) { 272 numChars--; 273 } 274 } else if (numChars + 1 < MAX_CHARS) { 275 int index = keyToGlyphIndex(event.key.keysym); 276 if (index >= 0) { 277 glyphs[numChars++] = index; 278 } 279 } 280 break; 281 case SDL_MOUSEBUTTONUP: 282 /* mouse up toggles onscreen keyboard visibility */ 283 if (SDL_IsTextInputActive()) { 284 SDL_StopTextInput(); 285 } else { 286 SDL_StartTextInput(); 287 } 288 break; 289 } 290 } 291 292 draw(); 293 SDL_Delay(15); 294 } 295 296 SDL_DestroyTexture(texture); 297 SDL_DestroyRenderer(renderer); 298 SDL_DestroyWindow(window); 299 SDL_Quit(); 300 return 0; 301 }