Checkbox

Collaboration diagram for Checkbox:

Data Structures
struct	CHECKBOX_STRUCT

Macros
#define	CHECKBOX_WIN_FG_COLOR   RGB(32,161,34)

Typedefs
typedef void(*	CHECKBOX_CALLBACK) (void *checkbox, bool checked)

Functions
bool	gui_checkbox_add (CHECKBOX_STRUCT *checkbox)
void	gui_checkbox_remove (CHECKBOX_STRUCT *checkbox)
void	gui_checkbox_update (CHECKBOX_STRUCT *checkbox)
void	gui_checkbox_redraw (CHECKBOX_STRUCT *checkbox)

Detailed Description

The Checkbox Gui-Element is a clickable, rectangular box with an optional tickmark inside of it. When the checkbox is pressed and released it's tick state changes and you will be notified via the provided callback.

Macro Definition Documentation

#define CHECKBOX_WIN_FG_COLOR   RGB(32,161,34)

Definition at line 82 of file checkbox.h.

Typedef Documentation

typedef void(* CHECKBOX_CALLBACK) (void *checkbox, bool checked)

Prototype for Event Listeners (called when the checkbox state has changed)

Note

You should NOT execute long running things in this callback nor should you update the gui. But you can call gui_screen_navigate() for instance.

Parameters

checkbox	The pointer to the CHECKBOX_STRUCT where to corresponding Checkbox has changed the state
checked	A boolean which indicates whether the checkbox is now checked or not.

Definition at line 45 of file checkbox.h.

Function Documentation

bool gui_checkbox_add

(

CHECKBOX_STRUCT *

checkbox

)

Adds a checkbox. Your Callback will be called from now on, if the checkbox changes state

Parameters

checkbox

A Pointer to the preinitialized CHECKBOX_STRUCT

Returns

true on success

Definition at line 70 of file checkbox.c.

{
    if (touch_have_empty(1)) { //Check if the touch module can handle one additional area
        unsigned char size = 0;
        checkbox->base.hookedActions = PEN_DOWN; //At first we are interested in PEN_DOWN events
        checkbox->base.callback = checkboxes_cb; //Use our own callback for the touch area events

        //Check the size of the checkbox
        if (checkbox->base.x2 > checkbox->base.x1) {
            size = checkbox->base.x2 - checkbox->base.x1;    //use width a as size
        }

        if (checkbox->base.y2 > checkbox->base.y1) {
            if ((checkbox->base.y2 - checkbox->base.y1) > size) { //height is larger than size
                size = checkbox->base.y2 - checkbox->base.y1;    //use height as size
            }
        }

        if (size == 0) { //no size found (maybe swap x2 and x1 or y2 and y1 ?)
            return false; //signal error
        }

        if ((size & 0x01)) { //the size is an odd number
            size++;    //make size an even number
        }

        //Correct x2,y2 so that the checkbox is quadratic
        checkbox->base.x2 = checkbox->base.x1 + size;
        checkbox->base.y2 = checkbox->base.y1 + size;

        gui_checkbox_redraw(checkbox);//Call redraw method, which will take care of the drawing of the entire checkbox

        return touch_register_area(&checkbox->base); //Register the touch area and receive events for this checkbox, from now on
    }

    return false; //no more touch areas left
}

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void gui_checkbox_redraw

(

CHECKBOX_STRUCT *

checkbox

)

Redraws the checkbox. Call this method if you have to redraw the entire screen or if you want to draw a checkbox on top of an image.

Parameters

checkbox

A Pointer to the CHECKBOX_STRUCT

Definition at line 108 of file checkbox.c.

{
    //Draw background and border
    tft_fill_rectangle(checkbox->base.x1 + 1, checkbox->base.y1 + 1, checkbox->base.x2 - 1, checkbox->base.y2 - 1, BACKGROUND_COLOR);
    tft_draw_rectangle(checkbox->base.x1, checkbox->base.y1, checkbox->base.x2, checkbox->base.y2, BORDER_COLOR);

    if (checkbox->checked) { //checkbox is currently checked
        gui_checkbox_update(checkbox); //Call update method which will draw the tickmark
    }
}

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void gui_checkbox_remove

(

CHECKBOX_STRUCT *

checkbox

)

Removes the checkbox. You will no longer receive events for this checkbox. This function will not overdraw the region where the checkbox was located.

Parameters

checkbox

A Pointer to the CHECKBOX_STRUCT

Definition at line 119 of file checkbox.c.

{
    //We only need to unregister the touch area, as we have not allocated anything else
    touch_unregister_area((TOUCH_AREA_STRUCT*)checkbox);
}

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void gui_checkbox_update

(

CHECKBOX_STRUCT *

checkbox

)

Updates the checkbox. Call this function when you change the state of the checkbox through code.

Parameters

checkbox

A Pointer to the CHECKBOX_STRUCT

Definition at line 125 of file checkbox.c.

{
    unsigned int c = (checkbox->checked) ? checkbox->fgcolor : BACKGROUND_COLOR; //color to use for the tickmark

    //helper points inside the checkbox
    unsigned int xcent = checkbox->base.x1 + (checkbox->base.x2 - checkbox->base.x1) * 6 / 14;
    unsigned int yleft = checkbox->base.y2 - (xcent - checkbox->base.x1) - 1 ;
    unsigned int yright = checkbox->base.y2 - (checkbox->base.x2 - xcent) - 1 ;
    unsigned int ybot = checkbox->base.y2 - 4;

    //Draw tickmark as a 3pixel wide line
    tft_draw_line(checkbox->base.x1 + 3, yleft - 1, xcent, ybot - 1, c);
    tft_draw_line(checkbox->base.x1 + 3, yleft, xcent, ybot , c);
    tft_draw_line(checkbox->base.x1 + 3, yleft + 1, xcent, ybot + 1, c);
    xcent++;
    ybot--;
    tft_draw_line(xcent, ybot - 1, checkbox->base.x2 - 3, yright - 1, c);
    tft_draw_line(xcent, ybot, checkbox->base.x2 - 3, yright + 0, c);
    tft_draw_line(xcent, ybot + 1, checkbox->base.x2 - 3, yright + 1, c);
}

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