CropAreaWidget Class Reference

The CropAreaWidget class Displays the image scaled to fit a reasonable dialog size, with a draggable, resizable crop rectangle overlaid on top – the area outside it dimmed, the usual visual convention for "this part goes away" during a crop, so it's never ambiguous which region survives. All internal geometry (the crop rect, drag handling, hit-testing) works in display-space pixel coordinates; only cropRect() converts back to the original, full-resolution image's own coordinates for the caller, the same original-vs-display distinction already used for colour sampling in ImageTransparentColorDialog. More...

#include <imagecropdialog.h>

Inherits QWidget.

Collaboration diagram for CropAreaWidget:

Public Slots
void	resetToFullImage ()
	CropAreaWidget::resetToFullImage.

Signals
void	cropRectChanged ()

Public Member Functions
	CropAreaWidget (const QImage &sourceImage, const QRect &initialCropRect=QRect(), QWidget *parent=nullptr)
	CropAreaWidget::CropAreaWidget.
QRect	cropRect () const
	CropAreaWidget::cropRect.

Protected Member Functions
void	paintEvent (QPaintEvent *event) override
	CropAreaWidget::paintEvent Draws the image, dims everything outside the crop rect (four strips around it, rather than one overlay with a hole cut out of it, since that would need a more involved clip/composition setup for no real benefit here), then the rect's own dashed border and its eight handles.
void	mousePressEvent (QMouseEvent *event) override
void	mouseMoveEvent (QMouseEvent *event) override
void	mouseReleaseEvent (QMouseEvent *event) override

Private Types
enum class	DragMode {   None , Move , ResizeN , ResizeS ,   ResizeE , ResizeW , ResizeNE , ResizeNW ,   ResizeSE , ResizeSW }

Private Member Functions
DragMode	handleAt (const QPoint &pos) const
	CropAreaWidget::handleAt.
void	applyDrag (const QPoint &pos)
	CropAreaWidget::applyDrag Recomputes m_cropRect from m_dragStartRect plus however far pos has moved from m_dragStartPos, according to m_dragMode – always clamped to stay within the displayed image and never smaller than MIN_CROP_SIZE, so the rect can never escape its bounds or collapse to nothing while being dragged.

Private Attributes
QImage	m_source
qreal	m_displayScale = 1.0
QRect	m_displayImageRect
QRect	m_cropRect
DragMode	m_dragMode = DragMode::None
QPoint	m_dragStartPos
QRect	m_dragStartRect

Static Private Attributes
static constexpr int	HANDLE_SIZE = 8
static constexpr int	MIN_CROP_SIZE = 16

Detailed Description

The CropAreaWidget class Displays the image scaled to fit a reasonable dialog size, with a draggable, resizable crop rectangle overlaid on top – the area outside it dimmed, the usual visual convention for "this part goes away" during a crop, so it's never ambiguous which region survives. All internal geometry (the crop rect, drag handling, hit-testing) works in display-space pixel coordinates; only cropRect() converts back to the original, full-resolution image's own coordinates for the caller, the same original-vs-display distinction already used for colour sampling in ImageTransparentColorDialog.

Member Enumeration Documentation

DragMode

enum class CropAreaWidget::DragMode

strongprivate

Enumerator
None
Move
ResizeN
ResizeS
ResizeE
ResizeW
ResizeNE
ResizeNW
ResizeSE
ResizeSW

Constructor & Destructor Documentation

CropAreaWidget()

CropAreaWidget::CropAreaWidget ( const QImage & sourceImage, const QRect & initialCropRect = QRect(), QWidget * parent = nullptr )

explicit

CropAreaWidget::CropAreaWidget.

Parameters

sourceImage	the full, uncropped image to crop from
initialCropRect	a previously-chosen crop rectangle, in sourceImage's own coordinates, to start from – an empty (default-constructed) QRect means "no previous crop", i.e. start covering the whole image.
sourceImage	the full-resolution image to crop
initialCropRect	a previously-chosen crop rect (in sourceImage's own coordinates), or an empty QRect to start covering the whole image
parent

Member Function Documentation

applyDrag()

void CropAreaWidget::applyDrag ( const QPoint & pos )

private

CropAreaWidget::applyDrag Recomputes m_cropRect from m_dragStartRect plus however far pos has moved from m_dragStartPos, according to m_dragMode – always clamped to stay within the displayed image and never smaller than MIN_CROP_SIZE, so the rect can never escape its bounds or collapse to nothing while being dragged.

Parameters

pos	current widget-space mouse position

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cropRect()

QRect CropAreaWidget::cropRect

(

)

const

CropAreaWidget::cropRect.

The current crop rectangle, in the original image's own coordinates (not display-space) – always clamped to the image's own bounds and never degenerate (zero width/height).

Returns

the crop rectangle in the original, full-resolution image's own coordinates – m_cropRect itself is display-space only.

cropRectChanged

void CropAreaWidget::cropRectChanged ( )

signal

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handleAt()

CropAreaWidget::DragMode CropAreaWidget::handleAt ( const QPoint & pos ) const

private

CropAreaWidget::handleAt.

Parameters

pos	widget-space position to test

Returns

whichever handle (or the rect's own interior, for moving) pos is close enough to, or DragMode::None if it's not near anything

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mouseMoveEvent()

void CropAreaWidget::mouseMoveEvent ( QMouseEvent * event )

overrideprotected

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mousePressEvent()

void CropAreaWidget::mousePressEvent ( QMouseEvent * event )

overrideprotected

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mouseReleaseEvent()

void CropAreaWidget::mouseReleaseEvent ( QMouseEvent * event )

overrideprotected

paintEvent()

void CropAreaWidget::paintEvent ( QPaintEvent * event )

overrideprotected

CropAreaWidget::paintEvent Draws the image, dims everything outside the crop rect (four strips around it, rather than one overlay with a hole cut out of it, since that would need a more involved clip/composition setup for no real benefit here), then the rect's own dashed border and its eight handles.

resetToFullImage

void CropAreaWidget::resetToFullImage ( )

slot

CropAreaWidget::resetToFullImage.

Resets the crop rectangle back to covering the entire image – the direct answer to "I want to undo the crop, not just adjust it", since dragging every handle back out by hand to exactly the original extent is needlessly fiddly.

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Member Data Documentation

HANDLE_SIZE

int CropAreaWidget::HANDLE_SIZE = 8

staticconstexprprivate

m_cropRect

QRect CropAreaWidget::m_cropRect

private

m_displayImageRect

QRect CropAreaWidget::m_displayImageRect

private

m_displayScale

qreal CropAreaWidget::m_displayScale = 1.0

private

m_dragMode

DragMode CropAreaWidget::m_dragMode = DragMode::None

private

m_dragStartPos

QPoint CropAreaWidget::m_dragStartPos

private

m_dragStartRect

QRect CropAreaWidget::m_dragStartRect

private

m_source

QImage CropAreaWidget::m_source

private

MIN_CROP_SIZE

int CropAreaWidget::MIN_CROP_SIZE = 16

staticconstexprprivate

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

• sources/ui/imagecropdialog.h
• sources/ui/imagecropdialog.cpp