/* Copyright (C) 2014 Karl Phillip Buhr <karlphillip@gmail.com>

*

* This work is licensed under the Creative Commons Attribution-ShareAlike License.

* To view a copy of this license, visit:

* https://creativecommons.org/licenses/by-sa/2.5/legalcode

*

* Or to read the human-readable summary of the license:

* https://creativecommons.org/licenses/by-sa/2.5/

*/

#include "time_canvas.h"

#include <cmath>

#include <QPainter>

#include <QDebug>

TimeCanvas::TimeCanvas(QFrame* parent, const QColor color)

: QFrame(parent), _color(color)

{

// Initialize class members

_x = _y = 50;

_dx = 2;

_dy = 1;

_sq_sz = 10;

// Set canvas size

setMinimumSize(175, 175);

}

void TimeCanvas::move(float dt)

{

/* Update position of square */

/* Rounding _dx up/down can affect the horizontal movement of the square.

* Rounding down when _dx is negative is essential to fix the slowness

* that happens when going from right to left.

*/

if (_dx > 0)

_x += std::ceil((_dx * dt * 60) / 1000); // (2 * 16 * 60) / 1000 = 1.92 = 2

else

_x += std::floor((_dx * dt * 60) / 1000); // (-2 * 16 * 60) / 1000 = -1.92 = -2

/* Rounding _dy up/down can also affect the vertical move of the square.

* If _dy is positive, round up, else the square will move sideways only.

* If _dy is negative, round down, else the square won't go up after colliding.

*/

if (_dy > 0)

_y += std::ceil((_dy * dt * 60) / 1000); // (1 * 16 * 60) / 1000 = 0.96 = 1

else

_y += std::floor((_dy * dt * 60) / 1000); // (-1 * 16 * 60) / 1000 = -0.96 = -1

if ( _x <= 0 || (_x >= (width()-1) - _sq_sz) ) {

_dx *= -1;

}

if ( _y <= 0 || (_y >= (height()-1) - _sq_sz) ) {

_dy *= -1;

}

}

void TimeCanvas::draw()

{

// Trigger paintEvent()

repaint();

}

void TimeCanvas::paintEvent(QPaintEvent* event)

{

QFrame::paintEvent(event);

/* Paint white background */

QPainter painter(this);

painter.fillRect(0, 0, width(), height(), Qt::white);

/* Paint black frame around the canvas */

painter.setPen(Qt::black);

painter.drawRect(0, 0, width()-1, height()-1);

/* Draw square */

painter.fillRect(_x, _y, _sq_sz, _sq_sz, _color);

}

void TimeCanvas::reset()

{

_x = _y = 50;

_dx = 2;

_dy = 1;

}