1 /*******************************************************************
2 *
3 * @file lv_example_gestures.c
4 *
5 * This is a simple example program that demonstrates how to use
6 * the gesture recognition API, please refer to lv_indev_gesture.h or the documentation
7 * for more details
8 *
9 * The application starts with a single rectangle that is scaled when a pinch gesture
10 * is detected. A single finger moves the rectangle around,
11 *
12 * Copyright (c) 2024 EDGEMTech Ltd
13 *
14 * Author: EDGEMTech Ltd, Erik Tagirov (erik.tagirov@edgemtech.ch)
15 *
16 ******************************************************************/
17
18 /*********************
19 * INCLUDES
20 *********************/
21 #include "../../lv_examples.h"
22
23 #if LV_USE_GESTURE_RECOGNITION && LV_BUILD_EXAMPLES
24
25 /*********************
26 * DEFINES
27 *********************/
28
29 #define RECT_INIT_WIDTH 300.0
30 #define RECT_INIT_HEIGHT 300.0
31 #define RECT_COLOR 0xC1BCFF
32
33 /**********************
34 * TYPEDEFS
35 **********************/
36
37 /**********************
38 * STATIC PROTOTYPES
39 **********************/
40
41 static void label_scale(lv_event_t * gesture_event);
42 static void label_move(lv_event_t * event);
43
44 /**********************
45 * STATIC VARIABLES
46 **********************/
47
48 static lv_obj_t * label;
49 static lv_style_t label_style;
50 static float label_width;
51 static float label_height;
52 static float label_x;
53 static float label_y;
54
55 /**********************
56 * MACROS
57 **********************/
58
59 /**********************
60 * GLOBAL FUNCTIONS
61 **********************/
62
63 /**
64 * Entry point it creates the screen, and the label
65 * Set event callbacks on the label
66 */
lv_example_gestures(void)67 void lv_example_gestures(void)
68 {
69 lv_obj_t * root_view;
70
71 label_width = RECT_INIT_WIDTH;
72 label_height = RECT_INIT_HEIGHT;
73 label_y = label_x = 300;
74
75 root_view = lv_screen_active();
76
77 lv_obj_set_style_bg_color(root_view, lv_color_hex(0xFFFFFF), LV_PART_MAIN);
78 label = lv_label_create(root_view);
79 lv_obj_remove_flag(root_view, LV_OBJ_FLAG_SCROLLABLE);
80
81 lv_label_set_text(label, "Zoom or move");
82 lv_obj_add_flag(label, LV_OBJ_FLAG_CLICKABLE);
83
84 lv_style_init(&label_style);
85 lv_style_set_bg_color(&label_style, lv_color_hex(RECT_COLOR));
86 lv_style_set_bg_opa(&label_style, LV_OPA_COVER);
87
88 lv_style_set_width(&label_style, (int)label_width);
89 lv_style_set_height(&label_style, (int)label_height);
90
91 lv_style_set_x(&label_style, (int)label_x);
92 lv_style_set_y(&label_style, (int)label_y);
93
94 lv_obj_add_style(label, &label_style, LV_STATE_DEFAULT);
95
96 lv_obj_add_event_cb(label, label_scale, LV_EVENT_GESTURE, label);
97 lv_obj_add_event_cb(label, label_move, LV_EVENT_PRESSING, label);
98
99 }
100
101 /**********************
102 * STATIC FUNCTIONS
103 **********************/
104
105 /**
106 * Called when a pinch event occurs - scales the label
107 * @param gesture_event point to a LV_EVENT_PINCH event
108 */
label_scale(lv_event_t * gesture_event)109 static void label_scale(lv_event_t * gesture_event)
110 {
111
112 static int initial_w = -1;
113 static int initial_h = -1;
114 lv_indev_gesture_state_t state;
115 lv_point_t center_pnt;
116 float scale;
117
118 scale = lv_event_get_pinch_scale(gesture_event);
119 state = lv_event_get_gesture_state(gesture_event);
120
121 lv_indev_get_point(lv_indev_active(), ¢er_pnt);
122
123 if(state == LV_INDEV_GESTURE_STATE_ENDED) {
124 /* Pinch gesture has ended - reset the width/height for the next pinch gesture*/
125 initial_w = -1;
126 initial_h = -1;
127
128 LV_LOG_USER("label end scale: %g, state: %d", scale, state);
129 return;
130 }
131
132 if(initial_h == -1 || initial_w == -1) {
133
134 LV_ASSERT(state == LV_INDEV_GESTURE_STATE_RECOGNIZED);
135
136 /* Pinch gesture has been recognized - this is the first event in a series of recognized events */
137 /* The scaling is applied relative to the original width/height of the rectangle */
138 initial_w = (int)label_width;
139 initial_h = (int)label_height;
140
141 LV_LOG_USER("label start scale: %g", scale);
142 }
143
144 /* The gesture has started or is on-going */
145
146 /* Avoids a situation where the rectangle becomes too small,
147 * do not perform the scaling - leave straight away */
148 if(scale < 0.4) {
149 return;
150 }
151
152 label_width = initial_w * scale;
153 label_height = initial_h * scale;
154 label_x = center_pnt.x - label_width / 2;
155 label_y = center_pnt.y - label_height / 2;
156
157 LV_LOG_USER("label scale: %g label x: %g label y: %g w: %g h: %g",
158 scale, label_x, label_y, label_width, label_height);
159
160 /* Update position and size */
161 lv_style_set_width(&label_style, (int)label_width);
162 lv_style_set_height(&label_style, (int)label_height);
163 lv_style_set_x(&label_style, (int)label_x);
164 lv_style_set_y(&label_style, (int)label_y);
165
166 lv_obj_add_style(label, &label_style, LV_STATE_DEFAULT);
167 }
168
169 /**
170 * Called when a LV_EVENT_PRESSING occurs on the rectangle - moves the label
171 * @param event pointer to the event
172 */
label_move(lv_event_t * event)173 static void label_move(lv_event_t * event)
174 {
175 lv_point_t pnt;
176 lv_indev_gesture_state_t state;
177
178 state = lv_event_get_gesture_state(event);
179 lv_indev_get_point(lv_indev_active(), &pnt);
180
181 /* Do not move and when a pinch gesture is ongoing */
182 if(state == LV_INDEV_GESTURE_STATE_RECOGNIZED) {
183 return;
184 }
185
186 LV_LOG_USER("label move x: %d, y: %d", pnt.x, pnt.y);
187
188 label_x = pnt.x - label_width / 2;
189 label_y = pnt.y - label_height / 2;
190
191 /* Update position */
192 lv_style_set_x(&label_style, (int)label_x);
193 lv_style_set_y(&label_style, (int)label_y);
194
195 lv_obj_add_style(label, &label_style, LV_STATE_DEFAULT);
196 }
197
198 #endif /* LV_USE_GESTURE_RECOGNITION && LV_USE_FLOAT */
199
