canvascursorpainter.cpp

/*
 
Pencil2D - Traditional Animation Software
Copyright (C) 2005-2007 Patrick Corrieri & Pascal Naidon
Copyright (C) 2012-2020 Matthew Chiawen Chang
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; version 2 of the License.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
*/
#include "canvascursorpainter.h"
 
#include <QPainter>
#include <QtMath>
 
CanvasCursorPainter::CanvasCursorPainter()
{
    setupPen();
}
 
void CanvasCursorPainter::setupPen()
{
    mCursorPen = QPen(Qt::gray);
    mCursorPen.setWidthF(1);
    mCursorPen.setCosmetic(true);
}
 
void CanvasCursorPainter::paint(QPainter& painter, const QRect& blitRect)
{
    if (mOptions.isAdjusting || mOptions.showCursor) {
        if (mOptions.useFeather) {
            paintFeatherCursor(painter, blitRect, mOptions.widthRect, mOptions.featherRect);
        }
        paintWidthCursor(painter, blitRect, mOptions.widthRect);
        mIsDirty = true;
    }
}
 
void CanvasCursorPainter::preparePainter(const CanvasCursorPainterOptions& painterOptions, const QTransform& viewTransform)
{
    mOptions = painterOptions;
    if (mOptions.isAdjusting || mOptions.showCursor) {
        // Apply full transform to center of widthRect, but only apply scale to the rect as a whole
        // Otherwise, view rotations will result in an incorrect rect size
        QPointF newCenter = viewTransform.map(mOptions.widthRect.center());
        qreal scale = qSqrt(qPow(viewTransform.m11(), 2) + qPow(viewTransform.m21(), 2));
        mOptions.widthRect.setSize(mOptions.widthRect.size() * scale);
        mOptions.widthRect.moveCenter(newCenter);
        mOptions.featherRect.setSize(mOptions.featherRect.size() * scale);
        mOptions.featherRect.moveCenter(newCenter);
    }
}
 
void CanvasCursorPainter::paintFeatherCursor(QPainter& painter, const QRect& blitRect, const QRectF& widthCircleBounds, const QRectF& featherCircleBounds)
{
    // When the circles are too close to each other, the rendering will appear dotted or almost
    // invisible at certain zoom levels.
    if (widthCircleBounds.width() - featherCircleBounds.width() <= 1) {
        return;
    }
 
    painter.save();
 
    painter.setClipRect(blitRect);
    painter.setPen(mCursorPen);
    painter.setCompositionMode(QPainter::RasterOp_SourceXorDestination);
    painter.drawEllipse(featherCircleBounds);
 
    painter.restore();
}
 
void CanvasCursorPainter::paintWidthCursor(QPainter& painter, const QRect& blitRect, const QRectF& widthCircleBounds)
{
    painter.save();
 
    painter.setClipRect(blitRect);
    painter.setPen(mCursorPen);
 
    painter.setCompositionMode(QPainter::RasterOp_SourceXorDestination);
 
    // Only draw the cross when the width is bigger than the cross itself
    if (widthCircleBounds.width() > 8) {
        const QPointF& pos = widthCircleBounds.center();
        painter.drawLine(QPointF(pos.x() - 2, pos.y()), QPointF(pos.x() + 2, pos.y()));
        painter.drawLine(QPointF(pos.x(), pos.y() - 2), QPointF(pos.x(), pos.y() + 2));
    }
 
    painter.drawEllipse(widthCircleBounds);
    painter.restore();
 
    mDirtyRect = widthCircleBounds.toAlignedRect();
}
 
void CanvasCursorPainter::clearDirty()
{
    mDirtyRect = QRect();
    mIsDirty = false;
}