KisQImagePyramid Class Reference

#include <kis_qimage_pyramid.h>

Classes
struct	PyramidLevel

Public Member Functions
QImage	createImage (KisDabShape const &, qreal subPixelX, qreal subPixelY) const
QImage	getClosest (QTransform transform, qreal *scale) const
QImage	getClosestWithoutWorkaroundBorder (QTransform transform, qreal *scale) const
	KisQImagePyramid ()=default
	KisQImagePyramid (const QImage &baseImage, bool useSmoothingForEnlarging=true)
	~KisQImagePyramid ()

Static Public Member Functions
static QSizeF	characteristicSize (const QSize &originalSize, KisDabShape const &)
static QSize	imageSize (const QSize &originalSize, KisDabShape const &, qreal subPixelX, qreal subPixelY)

Private Member Functions
void	appendPyramidLevel (const QImage &image)
int	findNearestLevel (qreal scale, qreal *baseScale) const

Static Private Member Functions
static void	calculateParams (KisDabShape const &shape, qreal subPixelX, qreal subPixelY, const QSize &originalSize, QTransform *outputTransform, QSize *outputSize)
static void	calculateParams (KisDabShape shape, qreal subPixelX, qreal subPixelY, const QSize &originalSize, qreal baseScale, const QSize &baseSize, QTransform *outputTransform, QSize *outputSize)

Private Attributes
qreal	m_baseScale {0.0}
QVector< PyramidLevel >	m_levels
QSize	m_originalSize

Friends
class	KisGbrBrushTest

Detailed Description

Definition at line 16 of file kis_qimage_pyramid.h.

Constructor & Destructor Documentation

KisQImagePyramid() [1/2]

KisQImagePyramid::KisQImagePyramid ( )

default

KisQImagePyramid() [2/2]

KisQImagePyramid::KisQImagePyramid	(	const QImage &	baseImage,
		bool	useSmoothingForEnlarging = true )

Definition at line 19 of file kis_qimage_pyramid.cpp.

{
    KIS_SAFE_ASSERT_RECOVER_RETURN(!baseImage.isNull());
 
    m_originalSize = baseImage.size();
 
 
    qreal scale = MAX_MIPMAP_SCALE;
 
    while (scale > 1.0) {
        QSize scaledSize = m_originalSize * scale;
 
        if (scaledSize.width() <= MIPMAP_SIZE_THRESHOLD ||
                scaledSize.height() <= MIPMAP_SIZE_THRESHOLD) {
 
            if (m_levels.isEmpty()) {
                m_baseScale = scale;
            }
 
            if (useSmoothingForEnlarging) {
                appendPyramidLevel(baseImage.scaled(scaledSize,  Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
            } else {
                appendPyramidLevel(baseImage.scaled(scaledSize,  Qt::IgnoreAspectRatio, Qt::FastTransformation));
            }
        }
 
        scale *= 0.5;
    }
 
    if (m_levels.isEmpty()) {
        m_baseScale = 1.0;
    }
    appendPyramidLevel(baseImage);
 
    scale = 0.5;
    while (true) {
        QSize scaledSize = m_originalSize * scale;
 
        if (scaledSize.width() == 0 ||
                scaledSize.height() == 0) break;
 
        appendPyramidLevel(baseImage.scaled(scaledSize,  Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
 
        scale *= 0.5;
    }
}

References appendPyramidLevel(), KIS_SAFE_ASSERT_RECOVER_RETURN, m_baseScale, m_levels, m_originalSize, MAX_MIPMAP_SCALE, and MIPMAP_SIZE_THRESHOLD.

~KisQImagePyramid()

KisQImagePyramid::~KisQImagePyramid

(

)

Definition at line 66 of file kis_qimage_pyramid.cpp.

{
}

Member Function Documentation

appendPyramidLevel()

void KisQImagePyramid::appendPyramidLevel ( const QImage & image )

private

QPainter has a bug: when doing a transformation it decides that all the pixels outside of the image (source rect) are equal to the border pixels (CLAMP in terms of openGL). This means that there will be no smooth scaling on the border of the image when it is rotated. To workaround this bug we need to add one pixel wide border to the image, so that it transforms smoothly.

See a unittest in: KisGbrBrushTest::testQPainterTransformationBorder

Definition at line 238 of file kis_qimage_pyramid.cpp.

{
QSize levelSize = image.size();
    QImage tmp = image.convertToFormat(QImage::Format_ARGB32);
    tmp = tmp.copy(-QPAINTER_WORKAROUND_BORDER,
                   -QPAINTER_WORKAROUND_BORDER,
                   image.width() + 2 * QPAINTER_WORKAROUND_BORDER,
                   image.height() + 2 * QPAINTER_WORKAROUND_BORDER);
    m_levels.append(PyramidLevel(tmp, levelSize));
}

References m_levels, and QPAINTER_WORKAROUND_BORDER.

calculateParams() [1/2]

void KisQImagePyramid::calculateParams ( KisDabShape const & shape, qreal subPixelX, qreal subPixelY, const QSize & originalSize, QTransform * outputTransform, QSize * outputSize )

staticprivate

Definition at line 134 of file kis_qimage_pyramid.cpp.

{
    calculateParams(shape,
                    subPixelX, subPixelY,
                    originalSize, 1.0, originalSize,
                    outputTransform, outputSize);
}

References calculateParams().

calculateParams() [2/2]

void KisQImagePyramid::calculateParams ( KisDabShape shape, qreal subPixelX, qreal subPixelY, const QSize & originalSize, qreal baseScale, const QSize & baseSize, QTransform * outputTransform, QSize * outputSize )

staticprivate

Definition at line 145 of file kis_qimage_pyramid.cpp.

{
    Q_UNUSED(baseScale);
 
    QRectF originalBounds = QRectF(QPointF(), originalSize);
    QTransform originalTransform = baseBrushTransform(shape, subPixelX, subPixelY, originalBounds);
 
    qreal realBaseScaleX = qreal(baseSize.width()) / originalSize.width();
    qreal realBaseScaleY = qreal(baseSize.height()) / originalSize.height();
    qreal scaleX = shape.scaleX() / realBaseScaleX;
    qreal scaleY = shape.scaleY() / realBaseScaleY;
    shape = KisDabShape(scaleX, scaleY/scaleX, shape.rotation());
 
    QRectF baseBounds = QRectF(QPointF(), baseSize);
    QTransform transform = baseBrushTransform(shape, subPixelX, subPixelY, baseBounds);
    QRectF mappedRect = originalTransform.mapRect(originalBounds);
 
    // Set up a 0,0,1,1 size and identity transform in case the transform fails to
    // produce a usable result.
    int width = 1;
    int height = 1;
    *outputTransform = QTransform();
 
    if (mappedRect.isValid()) {
        QRect expectedDstRect = roundRect(mappedRect);
 
#if 0 // Only enable when debugging; users shouldn't see this warning
        {
            QRect testingRect = roundRect(transform.mapRect(baseBounds));
            if (testingRect != expectedDstRect) {
                warnKrita << "WARNING: expected and real dab rects do not coincide!";
                warnKrita << "         expected rect:" << expectedDstRect;
                warnKrita << "         real rect:    " << testingRect;
            }
        }
#endif
        KIS_SAFE_ASSERT_RECOVER_NOOP(expectedDstRect.x() >= 0);
        KIS_SAFE_ASSERT_RECOVER_NOOP(expectedDstRect.y() >= 0);
 
        width = expectedDstRect.x() + expectedDstRect.width();
        height = expectedDstRect.y() + expectedDstRect.height();
 
        // we should not return invalid image, so adjust the image to be
        // at least 1 px in size.
        width = qMax(1, width);
        height = qMax(1, height);
    }
    else {
#if 0 // Only enable when debugging; users shouldn't see this warning
        qWarning() << "Brush transform generated an invalid rectangle!"
            << ppVar(shape.scaleX()) << ppVar(shape.scaleY()) << ppVar(shape.rotation())
            << ppVar(subPixelX) << ppVar(subPixelY)
            << ppVar(originalSize)
            << ppVar(baseScale)
            << ppVar(baseSize)
            << ppVar(baseBounds)
            << ppVar(mappedRect);
#endif
    }
 
    *outputTransform = transform;
    *outputSize = QSize(width, height);
}

References baseBrushTransform(), KIS_SAFE_ASSERT_RECOVER_NOOP, ppVar, KisDabShape::rotation(), roundRect(), KisDabShape::scaleX(), KisDabShape::scaleY(), and warnKrita.

characteristicSize()

QSizeF KisQImagePyramid::characteristicSize ( const QSize & originalSize, KisDabShape const & shape )

static

Definition at line 227 of file kis_qimage_pyramid.cpp.

{
    QRectF originalRect(QPointF(), originalSize);
    QTransform transform = baseBrushTransform(shape,
                                              0.0, 0.0,
                                              originalRect);
 
    return transform.mapRect(originalRect).size();
}

References baseBrushTransform().

createImage()

QImage KisQImagePyramid::createImage	(	KisDabShape const &	shape,
		qreal	subPixelX,
		qreal	subPixelY ) const

QPainter has one more bug: when a QTransform is TxTranslate, it does wrong sampling (probably, Nearest Neighbour) even though we tell it directly that we need SmoothPixmapTransform.

So here is a workaround: we set a negligible scale to convince Qt we use a non-only-translating transform.

Definition at line 260 of file kis_qimage_pyramid.cpp.

{
    if (m_levels.isEmpty()) return QImage();
 
    qreal baseScale = -1.0;
    int level = findNearestLevel(shape.scale(), &baseScale);
 
    const QImage &srcImage = m_levels[level].image;
 
    QTransform transform;
    QSize dstSize;
 
    calculateParams(shape, subPixelX, subPixelY,
                    m_originalSize, baseScale, m_levels[level].size,
                    &transform, &dstSize);
 
    if (transform.isIdentity() &&
            srcImage.format() == QImage::Format_ARGB32) {
 
        return srcImage.copy(QPAINTER_WORKAROUND_BORDER,
                             QPAINTER_WORKAROUND_BORDER,
                             srcImage.width() - 2 * QPAINTER_WORKAROUND_BORDER,
                             srcImage.height() - 2 * QPAINTER_WORKAROUND_BORDER);
    }
 
    QImage dstImage(dstSize, QImage::Format_ARGB32);
    dstImage.fill(0);
 
 
    while (transform.type() == QTransform::TxTranslate) {
        const qreal scale = transform.m11();
        const qreal fakeScale = scale - 10 * std::numeric_limits<qreal>::epsilon();
        transform *= QTransform::fromScale(fakeScale, fakeScale);
    }
 
    QPainter gc(&dstImage);
    gc.setTransform(
        QTransform::fromTranslate(-QPAINTER_WORKAROUND_BORDER,
                                  -QPAINTER_WORKAROUND_BORDER) * transform);
    gc.setRenderHints(QPainter::SmoothPixmapTransform);
    gc.drawImage(QPointF(), srcImage);
    gc.end();
 
    return dstImage;
}

References calculateParams(), findNearestLevel(), m_levels, m_originalSize, QPAINTER_WORKAROUND_BORDER, and KisDabShape::scale().

findNearestLevel()

int KisQImagePyramid::findNearestLevel ( qreal scale, qreal * baseScale ) const

private

Definition at line 70 of file kis_qimage_pyramid.cpp.

{
    const qreal scale_epsilon = 1e-6;
 
    qreal levelScale = m_baseScale;
    int level = 0;
    int lastLevel = m_levels.size() - 1;
 
 
    while ((0.5 * levelScale > scale ||
            qAbs(0.5 * levelScale - scale) < scale_epsilon) &&
            level < lastLevel) {
 
        levelScale *= 0.5;
        level++;
    }
 
    *baseScale = levelScale;
    return level;
}

References m_baseScale, and m_levels.

getClosest()

QImage KisQImagePyramid::getClosest	(	QTransform	transform,
		qreal *	scale ) const

Definition at line 315 of file kis_qimage_pyramid.cpp.

{
    if (m_levels.isEmpty()) return QImage();
 
    // Estimate scale
    QSizeF transformedUnitSquare = transform.mapRect(QRectF(0, 0, 1, 1)).size();
    qreal x = qAbs(transformedUnitSquare.width());
    qreal y = qAbs(transformedUnitSquare.height());
    qreal estimatedScale = (x > y) ? transformedUnitSquare.width() : transformedUnitSquare.height();
 
    int level = findNearestLevel(estimatedScale, scale);
    return m_levels[level].image;
}

References findNearestLevel(), and m_levels.

getClosestWithoutWorkaroundBorder()

QImage KisQImagePyramid::getClosestWithoutWorkaroundBorder	(	QTransform	transform,
		qreal *	scale ) const

Definition at line 329 of file kis_qimage_pyramid.cpp.

{
    QImage image = getClosest(transform, scale);
    return image.copy(QPAINTER_WORKAROUND_BORDER,
               QPAINTER_WORKAROUND_BORDER,
               image.width() - 2 * QPAINTER_WORKAROUND_BORDER,
               image.height() - 2 * QPAINTER_WORKAROUND_BORDER);
}

References getClosest(), and QPAINTER_WORKAROUND_BORDER.

imageSize()

QSize KisQImagePyramid::imageSize ( const QSize & originalSize, KisDabShape const & shape, qreal subPixelX, qreal subPixelY )

static

Definition at line 213 of file kis_qimage_pyramid.cpp.

{
    QTransform transform;
    QSize dstSize;
 
    calculateParams(shape, subPixelX, subPixelY,
                    originalSize,
                    &transform, &dstSize);
 
    return dstSize;
}

References calculateParams().

Friends And Related Symbol Documentation

KisGbrBrushTest

friend class KisGbrBrushTest

friend

Definition at line 37 of file kis_qimage_pyramid.h.

Member Data Documentation

m_baseScale

qreal KisQImagePyramid::m_baseScale {0.0}

private

Definition at line 54 of file kis_qimage_pyramid.h.

{0.0};

m_levels

QVector<PyramidLevel> KisQImagePyramid::m_levels

private

Definition at line 64 of file kis_qimage_pyramid.h.

m_originalSize

QSize KisQImagePyramid::m_originalSize

private

Definition at line 53 of file kis_qimage_pyramid.h.

---

The documentation for this class was generated from the following files:

• libs/brush/kis_qimage_pyramid.h
• libs/brush/kis_qimage_pyramid.cpp