SDL 2 gesture detection

gistfile1.c

#ifdef TCOD_ANDROID
#include <android/log.h>
#define MAX_GESTURE_COORDS 4000
#define MAX_GESTURES 3

#ifndef PRIs32
#define PRIs32 "d"
#endif

#ifndef PRIs64
#ifdef __WIN32__
#define PRIs64 "I64"
#else
#define PRIs64 "lld"
#endif
#endif

#define GESTURE_ERROR_RECORDING_OVERFLOW (1 << 0)
#define GESTURE_ERROR_RECORDING_DENIED (1 << 1)

void render_gesture_chars(unsigned short *coords, int min_coord, int max_coord) {
	int i, lcx, lcy;
	for (i=min_coord; i<max_coord; i++) {
		lcx = (int)coords[i*2+0];
		lcy = (int)coords[i*2+1];
		TCOD_console_set_char_background(NULL,lcx,lcy,TCOD_green,TCOD_BKGND_SET);
		TCOD_console_set_char(NULL,lcx,lcy,TCOD_CHAR_BLOCK3);
	}
}

void render_gestures(bool first, TCOD_key_t*key, TCOD_mouse_t *mouse) {
	SDL_Event event;
	SDL_Touch *touch;
	int i, cx=0, cy=1;
	TCOD_console_clear(sample_console);
	TCOD_console_set_default_foreground(sample_console,TCOD_white);
	if (SDL_GetNumTouch() == 1) {
		if (key->c == 'r') {
			if (SDL_RecordGesture(-1)) {
				int font_width, font_height;
				int fullscreen_offsetx, fullscreen_offsety;
				int scale_width, scale_height, actual_width, actual_height;
				int rows, cols, num_detections = 0, error_flags = 0, exit_keypress = 0, num_moves = 0;
				unsigned short num_coords = 0, num_gestures = 0;
				unsigned short coords[MAX_GESTURE_COORDS];
				unsigned short gestures[MAX_GESTURES];
				SDL_Event events[MAX_GESTURES];
				SDL_Event last_detect_event;

				TCOD_sys_get_char_size(&font_width, &font_height);
				TCOD_sys_get_fullscreen_offsets(&fullscreen_offsetx, &fullscreen_offsety);
				TCOD_sys_get_fullscreen_scale_size(&scale_width, &scale_height);
				TCOD_sys_get_fullscreen_size(&actual_width, &actual_height);
				cols = TCOD_console_get_width(NULL);
				rows = TCOD_console_get_height(NULL);

				/* Mark the start of the coords for the first gesture. */
				gestures[num_gestures] = num_coords;
				while (num_gestures < MAX_GESTURES || exit_keypress == 0) {
					int lcx, lcy;
					cx = SAMPLE_SCREEN_X+1;
					cy = SAMPLE_SCREEN_Y+1;
					/* Poor man's console clear. */
					TCOD_console_blit(sample_console,0,0,SAMPLE_SCREEN_WIDTH,SAMPLE_SCREEN_HEIGHT, /* the source console & zone to blit */
										NULL,SAMPLE_SCREEN_X,SAMPLE_SCREEN_Y, /* the destination console & position */
										1.0f,1.0f /* alpha coefs */
									 );
					TCOD_console_set_default_foreground(NULL,TCOD_white);
					TCOD_console_set_default_background(NULL,TCOD_black);
					if (error_flags & GESTURE_ERROR_RECORDING_DENIED) {
						TCOD_console_print(NULL,cx,cy++,"Failed recording a gesture:");
						TCOD_console_print(NULL,cx,cy++,"SDL wouldn't let you.");
					} else if (error_flags & GESTURE_ERROR_RECORDING_OVERFLOW) {
						TCOD_console_print(NULL,cx,cy++,"Failed recording a gesture:");
						TCOD_console_print(NULL,cx,cy++,"Too many motion events, no end detected.");
					} else {
						if (num_gestures < MAX_GESTURES) {
							render_gesture_chars(coords, gestures[num_gestures], num_coords);

							TCOD_console_print(NULL,cx,cy++,"Recording gesture %d/%d:                   ",num_gestures+1,MAX_GESTURES);
							TCOD_console_print(NULL,cx,cy++,"Press finger, move it, lift it.            ");
						} else {
							TCOD_console_print(NULL,cx,cy++,"Gesture detection test (%d known gestures).",MAX_GESTURES);
							TCOD_console_print(NULL,cx,cy++,"Press back key to exit at any time.        ");
						}

						cy+=5;
						for (i=0; i<num_gestures; i++) {
							TCOD_console_print(NULL,cx,cy++,"Recorded gesture %d: gestureId %"PRIs64" ",i+1,events[i].dgesture.gestureId);
						}
						cy+=2;
						if (num_detections > 0) {
							if (num_moves == 0) {
								int j;
								for (j=0; j<num_gestures; j++) {
									if (last_detect_event.dgesture.gestureId == events[j].dgesture.gestureId) {
										TCOD_console_print(NULL,cx,cy++,"Detected gesture #%d (%d gesture detections).", j+1, num_detections);
										TCOD_console_print(NULL,cx,cy++,"Error: %f", events[j].dgesture.error);

										if (j == MAX_GESTURES-1)
											render_gesture_chars(coords, gestures[j], num_coords);
										else
											render_gesture_chars(coords, gestures[j], gestures[j+1]);
										break;
									}
								}
							} else {
								TCOD_console_print(NULL,cx,cy++,"Detecting gesture, %d moves counted.", num_moves);
							}
						}
					}

					if (SDL_PollEvent(&event)) {
						SDL_TouchFingerEvent *event_finger;
						SDL_Touch *event_touch;
						int x, y;

						switch (event.type) {
						case SDL_FINGERMOTION:
							/* While a gesture is recording, display some visual indication. */
							if (num_gestures < MAX_GESTURES && error_flags == 0) {
								event_finger=&event.tfinger;
								event_touch=SDL_GetTouch(event_finger->touchId);
								x = (event_finger->x * actual_width)/event_touch->xres;
								y = (event_finger->y * actual_height)/event_touch->yres;
								if (scale_width != 0) {
									lcx = ((x - fullscreen_offsetx) * cols) / scale_width;
									lcy = ((y - fullscreen_offsety) * rows) / scale_height;
								} else {
									lcx = (x - fullscreen_offsetx) / font_width;
									lcy = (y - fullscreen_offsety) / font_height;
								}
								TCOD_console_set_char_background(NULL,lcx,lcy,TCOD_green,TCOD_BKGND_SET);
								TCOD_console_set_char(NULL,lcx,lcy,TCOD_CHAR_BLOCK3);

								if (num_coords*2 >= MAX_GESTURE_COORDS) {
									error_flags = GESTURE_ERROR_RECORDING_OVERFLOW;
								} else {
									coords[num_coords*2+0] = (unsigned short)lcx;
									coords[num_coords*2+1] = (unsigned short)lcy;
									num_coords += 1;
								}
							} else if (error_flags == 0) {
								num_moves += 1;
							}
							break;
						case SDL_KEYDOWN:
							/* A gesture was recorded, now wait for the user to acknowledge it. */
							if (num_gestures == MAX_GESTURES) {
								switch(event.key.keysym.scancode) {
								case SDL_SCANCODE_AC_BACK:
									exit_keypress = 1;
									break;
								}
							}
							break;
						case SDL_DOLLARRECORD:
							/* A gesture was being recorded, and SDL acknowledged it finished. */
							events[num_gestures] = event;
							num_gestures += 1;
							/* If there are further gestures to record, mark the start of their coords. */
							if (num_gestures < MAX_GESTURES) {
								gestures[num_gestures] = num_coords;
								/* Start SDL recording the next gesture. */
								if (!SDL_RecordGesture(-1))
									error_flags = GESTURE_ERROR_RECORDING_DENIED;
							}
							break;
						case SDL_DOLLARGESTURE:
							num_detections += 1;
							num_moves = 0;
							last_detect_event = event;
							break;
						}
					}
					TCOD_console_flush();
				}
			}
		} else {
			TCOD_console_print(sample_console,1,cy++,"Detected touch pads:");
			for (i=0; i<SDL_GetNumTouch();i++) {
				touch = (SDL_Touch*)SDL_GetTouchIndex(i);
				TCOD_console_print(sample_console,1,cy++,"#%d: %li %lx",i,touch->id,touch->id);
			}
			TCOD_console_print(sample_console,1,cy++,"Press 'r' to start recording.");
		}
	} else if (SDL_GetNumTouch() > 1) {
		TCOD_console_print(sample_console,1,cy++,"Too many touch pads.");
		TCOD_console_print(sample_console,1,cy++,"Programmer hasn't handled this.");
	} else {
		TCOD_console_print(sample_console,1,cy++,"No known touch pad.");
		TCOD_console_print(sample_console,1,cy++,"Please touch it, so SDL can see it.");
	}
}
#endif