User interface for mXT143E Xplained trackpad demo.

#include <asf.h>
#include <conf_example.h>
#include "ui.h"
#include "conf_usb.h"

Data Structures
struct	trace_info
	Information for one trace point. More...

Macros
Touch trace settings
#define	TRACE_RECT_SIZE 10
	Size (width/height) of trace-rectangle. More...

#define	NUM_TRACES 150
	Number of rectangles in the touch trace. More...

Functions
static void	draw_frame (const uint8_t start, const uint8_t thickness, const gfx_color_t color)
	Draw a frame. More...

static void	handle_trace (gfx_coord_t x, gfx_coord_t y)
	Handle finger traces on display. More...

void	ui_init (void)
	Initialize the user interface. More...

void	ui_powerdown (void)
	Put the user interface in power down. More...

void	ui_process (uint16_t framenumber)
	Process the user interface. More...

void	ui_wakeup (void)
	Wake the user interface up. More...

void	ui_wakeup_disable (void)
	Disable asynchronous interrupts of the user interface. More...

void	ui_wakeup_enable (void)
	Enable asynchronous interrupts of the user interface. More...

Variables
static struct trace_info	trace [NUM_TRACES]
	Array to hold all trace points. More...

bool	ui_new_touch_event
	Flag that a new touch event is pending. More...

struct mxt_touch_event	ui_touch_event
	Struct to hold touch events to process. More...

Display size containers
To avoid fetching the display size multiple times from the graphics service, store them in these two variables upon initialization.
static uint16_t	display_w
	Display width. More...

static uint16_t	display_h
	Display height. More...

#define NUM_TRACES 150

Number of rectangles in the touch trace.

Note: This macro essentially sets the length of the trace.

Referenced by handle_trace(), and ui_init().

#define TRACE_RECT_SIZE 10

Size (width/height) of trace-rectangle.

Referenced by handle_trace().

static void draw_frame	(	const uint8_t	start,
		const uint8_t	thickness,
		const gfx_color_t	color
	)

static

Draw a frame.

This function draws a frame with the specified thickness and color on the display, at the specified start offset from the edges.

Parameters

start	Start offset (x and y, from 0) of frame
thickness	Thickness (in pixels) of frame
color	Color of frame

References display_h, display_w, and gfx_draw_rect.

Referenced by ui_process().

static void handle_trace	(	gfx_coord_t	x,
		gfx_coord_t	y
	)

static

Handle finger traces on display.

This function updates the traces, drawing a new one at the specified coordinates and clearing the oldest one. It must be called at regular intervals to give a smooth trace animation.

Parameters

x	X-coordinate of finger touch
y	Y-coordinate of finger touch

Note: The coordinate (0,0) is used to indicate no touch, thus only causing the oldest trace to be cleared.

References COLOR_BACKGROUND, display_h, display_w, GFX_COLOR_WHITE, gfx_draw_rect, max, min, NUM_TRACES, trace, TRACE_RECT_SIZE, trace_info::x, and trace_info::y.

Referenced by ui_process().

void ui_init ( void )

Initialize the user interface.

References display_h, display_w, gfx_get_height(), gfx_get_width(), LED0_GPIO, LED1_GPIO, LED_Off, LED_On, NUM_TRACES, trace, ui_new_touch_event, trace_info::x, and trace_info::y.

Referenced by main().

void ui_powerdown ( void )

Put the user interface in power down.

References LED0_GPIO, LED1_GPIO, and LED_Off.

Referenced by main(), and main_suspend_action().

void ui_process ( uint16_t framenumber )

Process the user interface.

This function processes user touch events and updates the display.

The first registered touch is used to control the cursor. Its presence is indicated with a red frame around the display. When the cursor touch moves, its movement is visualized with a trace on the display.

The second registered touch is used to control mouse buttons, and is indicated with an inner frame of which the color depends on which side the touch is for: blue for left and green for right button click. The frame is shown until the touch is released. To detect which side click it is, the position relative to the cursor touch is used, i.e., a touch to the left of the first touch will cause a left mouse click.

Parameters

framenumber Current USB frame number