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 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
13 static SDL_Texture *texture; /* texture where we'll hold our font */
14
15 /* function declarations */
16 void cleanup(void);
17 void drawBlank(int x, int y);
18
19 static SDL_Renderer *renderer;
20 static int numChars = 0; /* number of characters we've typed so far */
21 static SDL_bool lastCharWasColon = 0; /* we use this to detect sequences such as :) */
22 static 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 */
29 typedef 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 */
45 fontMapping 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 */
109 int
keyToIndex(SDL_Keysym key)110 keyToIndex(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 */
132 void
getPositionForCharNumber(int n,int * x,int * y)133 getPositionForCharNumber(int n, int *x, int *y)
134 {
135 int renderW, renderH;
136 SDL_RenderGetLogicalSize(renderer, &renderW, &renderH);
137
138 int x_padding = 16; /* padding space on left and right side of screen */
139 int y_padding = 32; /* padding space at top of screen */
140 /* figure out the number of characters that can fit horizontally across the screen */
141 int max_x_chars = (renderW - 2 * x_padding) / GLYPH_SIZE_SCREEN;
142 int line_separation = 5; /* pixels between each line */
143 *x = (n % max_x_chars) * GLYPH_SIZE_SCREEN + x_padding;
144 *y = (n / max_x_chars) * (GLYPH_SIZE_SCREEN + line_separation) +
145 y_padding;
146 }
147
148 void
drawIndex(int index)149 drawIndex(int index)
150 {
151 int x, y;
152 getPositionForCharNumber(numChars, &x, &y);
153 SDL_Rect srcRect =
154 { GLYPH_SIZE_IMAGE * index, 0, GLYPH_SIZE_IMAGE, GLYPH_SIZE_IMAGE };
155 SDL_Rect dstRect = { x, y, GLYPH_SIZE_SCREEN, GLYPH_SIZE_SCREEN };
156 drawBlank(x, y);
157 SDL_RenderCopy(renderer, texture, &srcRect, &dstRect);
158 }
159
160 /* draws the cursor icon at the current end position of the text */
161 void
drawCursor(void)162 drawCursor(void)
163 {
164 drawIndex(29); /* cursor is at index 29 in the bitmap font */
165 }
166
167 /* paints over a glyph sized region with the background color
168 in effect it erases the area
169 */
170 void
drawBlank(int x,int y)171 drawBlank(int x, int y)
172 {
173 SDL_Rect rect = { x, y, GLYPH_SIZE_SCREEN, GLYPH_SIZE_SCREEN };
174 SDL_SetRenderDrawColor(renderer, bg_color.r, bg_color.g, bg_color.b, bg_color.a);
175 SDL_RenderFillRect(renderer, &rect);
176 }
177
178 /* moves backwards one character, erasing the last one put down */
179 void
backspace(void)180 backspace(void)
181 {
182 int x, y;
183 if (numChars > 0) {
184 getPositionForCharNumber(numChars, &x, &y);
185 drawBlank(x, y);
186 numChars--;
187 getPositionForCharNumber(numChars, &x, &y);
188 drawBlank(x, y);
189 drawCursor();
190 }
191 }
192
193 /* this function loads our font into an SDL_Texture and returns the SDL_Texture */
194 SDL_Texture*
loadFont(void)195 loadFont(void)
196 {
197
198 SDL_Surface *surface = SDL_LoadBMP("kromasky_16x16.bmp");
199
200 if (!surface) {
201 printf("Error loading bitmap: %s\n", SDL_GetError());
202 return 0;
203 } else {
204 /* set the transparent color for the bitmap font (hot pink) */
205 SDL_SetColorKey(surface, 1, SDL_MapRGB(surface->format, 238, 0, 252));
206 /* now we convert the surface to our desired pixel format */
207 int format = SDL_PIXELFORMAT_ABGR8888; /* desired texture format */
208 Uint32 Rmask, Gmask, Bmask, Amask; /* masks for desired format */
209 int bpp; /* bits per pixel for desired format */
210 SDL_PixelFormatEnumToMasks(format, &bpp, &Rmask, &Gmask, &Bmask,
211 &Amask);
212 SDL_Surface *converted =
213 SDL_CreateRGBSurface(0, surface->w, surface->h, bpp, Rmask, Gmask,
214 Bmask, Amask);
215 SDL_BlitSurface(surface, NULL, converted, NULL);
216 /* create our texture */
217 texture =
218 SDL_CreateTextureFromSurface(renderer, converted);
219 if (texture == 0) {
220 printf("texture creation failed: %s\n", SDL_GetError());
221 } else {
222 /* set blend mode for our texture */
223 SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
224 }
225 SDL_FreeSurface(surface);
226 SDL_FreeSurface(converted);
227 return texture;
228 }
229 }
230
231 int
main(int argc,char * argv[])232 main(int argc, char *argv[])
233 {
234 int index; /* index of last key we pushed in the bitmap font */
235 SDL_Window *window;
236 SDL_Event event; /* last event received */
237 SDL_Keymod mod; /* key modifiers of last key we pushed */
238 SDL_Scancode scancode; /* scancode of last key we pushed */
239 int width;
240 int height;
241
242 if (SDL_Init(SDL_INIT_VIDEO) < 0) {
243 printf("Error initializing SDL: %s", SDL_GetError());
244 }
245 /* create window */
246 window = SDL_CreateWindow("iPhone keyboard test", 0, 0, 320, 480, SDL_WINDOW_ALLOW_HIGHDPI);
247 /* create renderer */
248 renderer = SDL_CreateRenderer(window, -1, 0);
249
250 SDL_GetWindowSize(window, &width, &height);
251 SDL_RenderSetLogicalSize(renderer, width, height);
252
253 /* load up our font */
254 loadFont();
255
256 /* draw the background, we'll just paint over it */
257 SDL_SetRenderDrawColor(renderer, bg_color.r, bg_color.g, bg_color.b, bg_color.a);
258 SDL_RenderFillRect(renderer, NULL);
259 SDL_RenderPresent(renderer);
260
261 int done = 0;
262 /* loop till we get SDL_Quit */
263 while (!done && SDL_WaitEvent(&event)) {
264 switch (event.type) {
265 case SDL_QUIT:
266 done = 1;
267 break;
268 case SDL_KEYDOWN:
269 index = keyToIndex(event.key.keysym);
270 scancode = event.key.keysym.scancode;
271 mod = event.key.keysym.mod;
272 if (scancode == SDL_SCANCODE_DELETE) {
273 /* if user hit delete, delete the last character */
274 backspace();
275 lastCharWasColon = 0;
276 } else if (lastCharWasColon && scancode == SDL_SCANCODE_0
277 && (mod & KMOD_SHIFT)) {
278 /* if our last key was a colon and this one is a close paren, the make a hoppy face */
279 backspace();
280 drawIndex(32); /* index for happy face */
281 numChars++;
282 drawCursor();
283 lastCharWasColon = 0;
284 } else if (index != -1) {
285 /* if we aren't doing a happy face, then just draw the normal character */
286 drawIndex(index);
287 numChars++;
288 drawCursor();
289 lastCharWasColon =
290 (event.key.keysym.scancode == SDL_SCANCODE_SEMICOLON
291 && (event.key.keysym.mod & KMOD_SHIFT));
292 }
293 /* check if the key was a colon */
294 /* draw our updates to the screen */
295 SDL_RenderPresent(renderer);
296 break;
297 case SDL_MOUSEBUTTONUP:
298 /* mouse up toggles onscreen keyboard visibility */
299 if (SDL_IsTextInputActive()) {
300 SDL_StopTextInput();
301 } else {
302 SDL_StartTextInput();
303 }
304 break;
305 }
306 }
307 cleanup();
308 return 0;
309 }
310
311 /* clean up after ourselves like a good kiddy */
312 void
cleanup(void)313 cleanup(void)
314 {
315 SDL_DestroyTexture(texture);
316 SDL_Quit();
317 }
318