numupdown.c

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/**************************************************************************************************************************************
* Project:       discoverpixy
* Website:       https://github.com/t-moe/discoverpixy
* Authors:       Aaron Schmocker, Timo Lang
* Institution:   BFH Bern University of Applied Sciences
* File:          common/gui/numupdown.c
*
* Version History:
* Date          Autor Email         SHA     Changes
* 2015-04-30    timolang@gmail.com  76ea9d8 Added num up down support.
* 2015-04-30    timolang@gmail.com  b491b78 Made numupdown horizontal
* 2015-05-15    timolang@gmail.com  9a16865 Added doxgen comments to filesyste, checkbox, numupdown and screen module. And some minor changes to the other modules.
* 2015-05-17    timolang@gmail.com  2d46336 Improved comments in implementation of button, checkbox, numupdown, tft, touch and screen modules/submodules.
*
**************************************************************************************************************************************/

#include "tft.h"
#include "touch.h"
#include "button.h"
#include "numupdown.h"
#include <stdio.h> //for sprintf
#include <stddef.h> //for offsetof macro
#include <stdlib.h> //for abs

/* The idea is as follows:
 * When the user add's a numupdown we create two buttons, one with a plus and one with a minus sign in it
 * When the user presses one of the buttons we check and increase the value and execute the provided user callback
 */


#define BASE_COLOR RGB(90,90,90) //Background color for the whole element

//Callback which is called when the user presses the "plus" button
void button_up_cb(void* button)
{
    //Get the pointer to the numupdown: subtract the offset of the buttonUp member in the struct from the button pointer
    NUMUPDOWN_STRUCT* element = button - offsetof(NUMUPDOWN_STRUCT, buttonUp);

    if (element->value < element->max) { //old value lies below the maximum
        element->value++; //let's increase the value
        gui_numupdown_update(element); //and redraw everything

        if (element->callback != NULL) { //the user provided a callback
            element->callback(element, element->value); //Call the user callback with the new value
        }
    }
}

//Callback which is called when the user presses the "minus" button
void button_down_cb(void* button)
{
    //Get the pointer to the numupdown: subtract the offset of the buttonDown member in the struct from the button pointer
    NUMUPDOWN_STRUCT* element = button - offsetof(NUMUPDOWN_STRUCT, buttonDown);

    if (element->value > element->min) { //old value lies above the minimum
        element->value--; //let's decrease the value
        gui_numupdown_update(element); //and redraw everything

        if (element->callback != NULL) { //the user provided a callback
            element->callback(element, element->value); //Call the user callback with the new value
        }
    }
}

//Method to calculate the number of characters needed to print the provided number in decimal notation (with optional sign)
static uint8_t calc_text_width(int16_t val)
{
    uint8_t width = 1 + (val < 0); //1 if positive, 2 if negative (to let space for sign)
    val = abs(val); //Make the number positive

    while (val >= 10) { //while we have two or more digits
        val /= 10; //remove one digit
        width++; //add one character
    }

    return width;
}


bool gui_numupdown_add(NUMUPDOWN_STRUCT* numupdown)
{
    if (touch_have_empty(2)) { //Check if the touch module can handle two additional areas
        if (numupdown->min > numupdown->max) { //min is bigger than max?
            return false; //invalid parameter
        }

        if (numupdown->value < numupdown->min) { //value is smaller than min?
            numupdown->value = numupdown->min; //normalize value
        } else if (numupdown->value > numupdown->max) { //value is bigger than max?
            numupdown->value = numupdown->max;  //normalize value
        }

        uint8_t tw1 = calc_text_width(numupdown->max); //Calculate character width to render maximum value
        uint8_t tw2 = calc_text_width(numupdown->min); //Calculate character width to render minimum value

        if (tw2 > tw1) {
            tw1 = tw2;    //ensure tw1 contains the larger number of the two
        }

        uint8_t width = tft_font_width(0) * (tw1 + 1); //Calculate width of the number area

        //Add "minus" button to the left side of the number area
        numupdown->buttonDown.base.x1 = numupdown->x;
        numupdown->buttonDown.base.y1 = numupdown->y;
        numupdown->buttonDown.base.x2 = AUTO;
        numupdown->buttonDown.base.y2 = numupdown->y + tft_font_height(0) * 2;
        numupdown->buttonDown.text = "-";
        numupdown->buttonDown.font = 0;
        numupdown->buttonDown.bgcolor = BASE_COLOR;
        numupdown->buttonDown.txtcolor = WHITE;
        numupdown->buttonDown.callback = button_down_cb;
        gui_button_add(&numupdown->buttonDown);

        //Add "plus" button to the right side of the number area
        numupdown->buttonUp.base.x1 = numupdown->buttonDown.base.x2 + width + 2;
        numupdown->buttonUp.base.y1 = numupdown->y;
        numupdown->buttonUp.base.x2 = AUTO;
        numupdown->buttonUp.base.y2 = numupdown->y + tft_font_height(0) * 2;
        numupdown->buttonUp.text = "+";
        numupdown->buttonUp.font = 0;
        numupdown->buttonUp.bgcolor = BASE_COLOR;
        numupdown->buttonUp.txtcolor = WHITE;
        numupdown->buttonUp.callback = button_up_cb;
        gui_button_add(&numupdown->buttonUp);

        //Draw background and label of the number area
        tft_fill_rectangle(numupdown->buttonDown.base.x2 + 2, numupdown->y, numupdown->buttonDown.base.x2 + width, numupdown->buttonUp.base.y2, BASE_COLOR);
        tft_print_formatted(numupdown->buttonDown.base.x2 + 2 + tft_font_width(0) / 2, numupdown->y + tft_font_height(0) / 2, numupdown->fgcolor, BASE_COLOR, 0, "%*d", tw1, numupdown->value);

        return true;
    }

    return false; //not enough touch areas left
}

void gui_numupdown_remove(NUMUPDOWN_STRUCT* numupdown)
{
    //remove the two buttons, we have no other allocated resources
    gui_button_remove(&numupdown->buttonUp);
    gui_button_remove(&numupdown->buttonDown);
}


void gui_numupdown_redraw(NUMUPDOWN_STRUCT* numupdown)
{
    //redraw the two buttons
    gui_button_redraw(&numupdown->buttonUp);
    gui_button_redraw(&numupdown->buttonDown);

    //call update method which will take care of the number-area rendering
    gui_numupdown_update(numupdown);
}

void gui_numupdown_update(NUMUPDOWN_STRUCT* numupdown)
{
    //Calculate the number area width again (see above)
    uint8_t tw1 = calc_text_width(numupdown->max);
    uint8_t tw2 = calc_text_width(numupdown->min);

    if (tw2 > tw1) {
        tw1 = tw2;
    }

    uint8_t width = tft_font_width(0) * (tw1 + 1);

    //Draw background and label of the number area
    tft_fill_rectangle(numupdown->buttonDown.base.x2 + 2, numupdown->y, numupdown->buttonDown.base.x2 + width, numupdown->buttonUp.base.y2, BASE_COLOR);
    tft_print_formatted(numupdown->buttonDown.base.x2 + 2 + tft_font_width(0) / 2, numupdown->y + tft_font_height(0) / 2, numupdown->fgcolor, BASE_COLOR, 0, "%*d", tw1, numupdown->value);
}