Added line-to-circle intersection code.

[architektonas] / src / painter.cpp

//
// painter.cpp: Paint abstraction layer between Archtektonas and Qt
//
// Part of the Architektonas Project
// (C) 2011 Underground Software
// See the README and GPLv3 files for licensing and warranty information
//
// JLH = James Hammons <jlhamm@acm.org>
//
// WHO  WHEN        WHAT
// ---  ----------  ------------------------------------------------------------
// JLH  09/20/2011  Created this file
//

#include "painter.h"
#include "global.h"
#include "mathconstants.h"


// Set class variable defaults
//Vector Painter::origin(-10.0, -10.0);
//double Painter::zoom = 1.0;
//Vector Painter::screenSize(200.0, 200.0);


Painter::Painter(QPainter * p/*= NULL*/): painter(p)
{
}


Painter::~Painter()
{
}


Vector Painter::CartesianToQtCoords(Vector v)
{
        // Convert regular Cartesian coordinates to the inverted Y-axis Qt coordinates
        // at the current origin and zoom level.
        return Vector((v.x - Global::origin.x) * Global::zoom, Global::screenSize.y - ((v.y - Global::origin.y) * Global::zoom));
}


Vector Painter::QtToCartesianCoords(Vector v)
{
        // Convert screen location, with inverted Y-axis coordinates, to regular
        // Cartesian coordinates at the current zoom level.
        return Vector((v.x / Global::zoom) + Global::origin.x, ((Global::screenSize.y - v.y) / Global::zoom) + Global::origin.y);
/*
How to do it:

e.g., we have a point on the screen at Qt coords of 10, 10, screenSize is 100, 100.
origin is -10, -10 and zoom level is 2 (200%)

1st, invert the Y: 10, 10 -> 10, 90
2nd, add origin:   10, 90 ->  0, 80 (no, not right--err, yes, it is)
3rd, aply zoom:     0, 80 ->  0, 40

or, is it:

1st, invert the Y: 10, 10 -> 10, 90
2nd, aply zoom:    10, 90 ->  5, 45
3rd, add origin:    5, 45 -> -5, 35

it depends on whether or not origin is in Qt coords or cartesian. If Qt, then the 1st
is correct, otherwise, the 2nd is correct.

The way we calculate the Cartesian to Qt shows the 2nd (origin is cartesian) to be correct.
*/
}


void Painter::SetRenderHint(int hint)
{
        if (!painter)
                return;

        painter->setRenderHint((QPainter::RenderHint)hint);
}


void Painter::SetPen(QPen pen)
{
        if (!painter)
                return;

        painter->setPen(pen);
}


void Painter::SetPen(uint32_t color, float size/*= 0*/, int style/*= 0*/)
{
        if (!painter)
                return;

        // We can cast style as Qt:PenStyle because they line up 1-to-1
        painter->setPen(QPen(QColor(color >> 16, (color >> 8) & 0xFF, color & 0xFF, 255),
                size, (Qt::PenStyle)style));
}


void Painter::SetBrush(QBrush brush)
{
        if (!painter)
                return;

        painter->setBrush(brush);
}


void Painter::SetBrush(uint32_t color)
{
        if (!painter)
                return;

        painter->setBrush(QBrush(QColor(color >> 16, (color >> 8) & 0xFF, color & 0xFF, 255)));
}


void Painter::SetFont(QFont font)
{
        if (!painter)
                return;

        painter->setFont(font);
}


void Painter::DrawAngledText(Vector center, double angle, QString text, double size)
{
        if (!painter)
                return;

        // Strategy: Since Qt doesn't have any rotated text drawing functions,
        // we instead translate the origin to the center of the text to be drawn and
        // then rotate the frame to the desired angle.
        center = CartesianToQtCoords(center);

        // We may need this stuff... If dimension text is large enough.
//      int textWidth = QFontMetrics(painter->font()).width(text);
//      int textHeight = QFontMetrics(painter->font()).height();
        QRectF textBox(-100.0 * Global::zoom * size, -100.0 * Global::zoom * size, 200.0 * Global::zoom * size, 200.0 * Global::zoom * size);   // x, y, w, h; x/y = upper left corner

        // This is in pixels. Might not render correctly at all zoom levels.
        // Need to figure out if dimensions are always rendered at one size
        // regardless of zoom, or if they have a definite size, and are thus
        // zoomable.
        float yOffset = -12.0 * Global::zoom * size;

        // Fix text so it isn't upside down...
#if 0
        if ((angle > PI * 0.5) && (angle < PI * 1.5))
        {
                angle += PI;
                yOffset = 12.0 * Global::zoom * size;
        }
#else
        if ((angle > QTR_TAU) && (angle < THREE_QTR_TAU))
        {
                angle += HALF_TAU;
                yOffset = 12.0 * Global::zoom * size;
        }
#endif

        textBox.translate(0, yOffset);
        painter->save();
        painter->translate(center.x, center.y);
        // Angles are backwards in the Qt coord system, so we flip ours...
        painter->rotate(-angle * RADIANS_TO_DEGREES);
//Need to fix this so the text scales as well...
        painter->drawText(textBox, Qt::AlignCenter, text);
        painter->restore();
}


//
// Draw angled text. Draws text using point p as the upper left corner.
// Size is point size, angle is in radians (defaults to 0).
//
void Painter::DrawTextObject(Point p, QString text, double size, double angle/*= 0*/)
{
        if (!painter)
                return;

        p = CartesianToQtCoords(p);
        painter->setFont(QFont("Arial", Global::zoom * size));
        int textWidth = QFontMetrics(painter->font()).width(text);
        int textHeight = QFontMetrics(painter->font()).height();

        QRectF textBox(0, 0, textWidth, textHeight);
        painter->save();
        painter->translate(p.x, p.y);
        // Angles are backwards in the Qt coord system, so we flip ours...
        painter->rotate(-angle * RADIANS_TO_DEGREES);
        painter->drawText(textBox, Qt::AlignLeft | Qt::AlignTop , text);
        painter->restore();
}


void Painter::DrawArc(Vector center, double radius, double startAngle, double span)
{
        center = CartesianToQtCoords(center);
        // Need to multiply scalar quantities by the zoom factor as well...
        radius *= Global::zoom;
        QRectF rectangle(QPointF(center.x - radius, center.y - radius),
                QPointF(center.x + radius, center.y + radius));
        int angle1 = (int)(startAngle * RADIANS_TO_DEGREES * 16.0);
        int angle2 = (int)(span * RADIANS_TO_DEGREES * 16.0);
        painter->drawArc(rectangle, angle1, angle2);
}


void Painter::DrawEllipse(Vector center, double axis1, double axis2)
{
        // Need to multiply scalar quantities by the zoom factor as well...
        center = CartesianToQtCoords(center);
        painter->drawEllipse(QPointF(center.x, center.y), axis1 * Global::zoom, axis2 * Global::zoom);
}


// This function is for drawing object handles without regard for zoom level;
// we don't want our object handle size to depend on the zoom level!
void Painter::DrawHandle(Vector center)
{
        center = CartesianToQtCoords(center);
        painter->setPen(QPen(Qt::red, 2.0, Qt::DotLine));
        painter->setBrush(Qt::NoBrush);
        painter->drawEllipse(QPointF(center.x, center.y), 4.0, 4.0);
}


// This function is for drawing object handles without regard for zoom level;
// we don't want our object handle size to depend on the zoom level!
void Painter::DrawArrowHandle(Vector center, double angle)
{
        center = CartesianToQtCoords(center);
        QPolygonF arrow;

        // Since we're drawing directly on the screen, the Y is inverted. So we use
        // the mirror of the angle.
        double orthoAngle = -angle + QTR_TAU;//(PI / 2.0);
        Vector orthogonal = Vector(cos(orthoAngle), sin(orthoAngle));
        Vector unit = Vector(cos(-angle), sin(-angle));

        Point p0 = center + (unit * 6.0);
        Point p1 = center + (unit * 21.0);
        Point p1b = center + (unit * 11.0);
        Point p2 = p1b + (orthogonal * 5.0);
        Point p3 = p1b - (orthogonal * 5.0);

        painter->drawLine(p0.x, p0.y, p1.x, p1.y);
        arrow << QPointF(p1.x, p1.y) << QPointF(p2.x, p2.y) << QPointF(p3.x, p3.y);

        painter->drawPolygon(arrow);
}


// This function is for drawing object handles without regard for zoom level;
// we don't want our object handle size to depend on the zoom level!
void Painter::DrawArrowToLineHandle(Vector center, double angle)
{
        DrawArrowHandle(center, angle);
        center = CartesianToQtCoords(center);

        // Since we're drawing directly on the screen, the Y is inverted. So we use
        // the mirror of the angle.
        double orthoAngle = -angle + QTR_TAU;//(PI / 2.0);
        Vector orthogonal = Vector(cos(orthoAngle), sin(orthoAngle));
        Vector unit = Vector(cos(-angle), sin(-angle));

        Point p1 = center + (unit * 21.0);
        Point p2 = p1 + (orthogonal * 7.0);
        Point p3 = p1 - (orthogonal * 7.0);

        painter->drawLine(p2.x, p2.y, p3.x, p3.y);
}


void Painter::DrawLine(int x1, int y1, int x2, int y2)
{
        if (!painter)
                return;

        Vector v1 = CartesianToQtCoords(Vector(x1, y1));
        Vector v2 = CartesianToQtCoords(Vector(x2, y2));
        painter->drawLine(v1.x, v1.y, v2.x, v2.y);
}


void Painter::DrawLine(Vector v1, Vector v2)
{
        if (!painter)
                return;

        v1 = CartesianToQtCoords(v1);
        v2 = CartesianToQtCoords(v2);
        painter->drawLine(QPointF(v1.x, v1.y), QPointF(v2.x, v2.y));
}


void Painter::DrawPoint(int x, int y)
{
        if (!painter)
                return;

        Vector v = CartesianToQtCoords(Vector(x, y));
        painter->drawPoint(v.x, v.y);
}


// The rect passed in is in Qt coordinates...
void Painter::DrawRoundedRect(QRectF rect, double radiusX, double radiusY)
{
        if (!painter)
                return;

        painter->drawRoundedRect(rect, radiusX, radiusY);
}


// The rect passed in is in Cartesian but we want to pad it by a set number of
// pixels (currently set at 8), so the pad looks the same regardless of zoom.
void Painter::DrawPaddedRect(QRectF rect)
{
        if (!painter)
                return;

        Vector v1 = CartesianToQtCoords(Vector(rect.x(), rect.y()));
        Vector v2 = CartesianToQtCoords(Vector(rect.right(), rect.bottom()));
        QRectF screenRect(QPointF(v1.x, v1.y), QPointF(v2.x, v2.y));
        screenRect.adjust(-8, 8, 8, -8);        // Left/top, right/bottom
        painter->drawRect(screenRect);
}


void Painter::DrawRect(QRectF rect)
{
        if (!painter)
                return;

        Vector v1 = CartesianToQtCoords(Vector(rect.x(), rect.y()));
        Vector v2 = CartesianToQtCoords(Vector(rect.right(), rect.bottom()));
        QRectF screenRect(QPointF(v1.x, v1.y), QPointF(v2.x, v2.y));
        painter->drawRect(screenRect);
}


void Painter::DrawText(QRectF rect, int type, QString text)
{
        if (!painter)
                return;

        painter->drawText(rect, (Qt::AlignmentFlag)type, text);
}


void Painter::DrawArrowhead(Vector head, Vector tail, double size)
{
        if (!painter)
                return;

        QPolygonF arrow;

        // We draw the arrowhead aligned along the line from tail to head
        double angle = Vector(head - tail).Angle();
        double orthoAngle = angle + QTR_TAU;//(PI / 2.0);
        Vector orthogonal = Vector(cos(orthoAngle), sin(orthoAngle));
        Vector unit = Vector(head - tail).Unit();

        Point p1 = head - (unit * 9.0 * size);
        Point p2 = p1 + (orthogonal * 3.0 * size);
        Point p3 = p1 - (orthogonal * 3.0 * size);

        Point p4 = CartesianToQtCoords(head);
        Point p5 = CartesianToQtCoords(p2);
        Point p6 = CartesianToQtCoords(p3);

        arrow << QPointF(p4.x, p4.y) << QPointF(p5.x, p5.y) << QPointF(p6.x, p6.y);

        painter->drawPolygon(arrow);
}


// Point is given in Cartesian coordinates
void Painter::DrawCrosshair(Vector point)
{
        if (!painter)
                return;

        Vector screenPoint = CartesianToQtCoords(point);
        painter->drawLine(0, screenPoint.y, Global::screenSize.x, screenPoint.y);
        painter->drawLine(screenPoint.x, 0, screenPoint.x, Global::screenSize.y);
}


void Painter::DrawInformativeText(QString text)
{
        painter->setFont(*Global::font);
        QRectF bounds = painter->boundingRect(QRectF(), Qt::AlignVCenter, text);
        bounds.moveTo(17.0, 17.0);
        QRectF textRect = bounds;
        textRect.adjust(-7.0, -7.0, 7.0, 7.0);

        QPen pen = QPen(QColor(0x00, 0xFF, 0x00), 1.0, Qt::SolidLine);
        painter->setPen(pen);
        painter->setBrush(QBrush(QColor(0x40, 0xFF, 0x40, 0x9F)));
        painter->drawRoundedRect(textRect, 7.0, 7.0);

        pen = QPen(QColor(0x00, 0x5F, 0xDF));
        painter->setPen(pen);
        painter->drawText(bounds, Qt::AlignVCenter, text);
}