BeatGraphLabel Class Reference

#include <beatgraph-label.h>

Public Slots
virtual void	drawCursor ()
virtual void	setImage (QImage I, wunsigned8 samplespercol)
Public Member Functions
	BeatGraphLabel (QWidget parent, const char name=0)
void	activate ()
void	deactivate ()
virtual	~BeatGraphLabel ()
Public Attributes
QTimer	timer
unsigned8	samples_per_column_diskrate
bool	cues_changed
Protected Member Functions
virtual void	paintEvent (QPaintEvent *)
virtual void	resizeEvent (QResizeEvent *event)
void	drawCueText ()
void	moveRuler (int &x1, int &x2, int &x3, int &x4)
Protected Attributes
QImage	original
QImage	resized
int	ruler_x

Detailed Description

The port from Qt3 to Qt4 is a bit tricky here. First: the new painter system does not allow us to draw outside a paint event message, so we need to fake these. Secondly: the double buffering makes the xor operation effectively useless. Third: removing the old line with a small redraw will redraw the entire bitmap regardless. These 3 reasons forced me to redraw the content of the window myself by updating the resized QPixMap. The result is that drawCursor will always update the image in a way that only leaves 1 line on the image. Once the image is updated we either request two paint operations (if the lines are far apart), or 1 merged operation if they are close to each other.

Constructor & Destructor Documentation

BeatGraphLabel::BeatGraphLabel	(	QWidget *	parent,
		const char *	name = `0`
	)

Creates a beatgraph label to be used in BpmPlay.

References cues_changed, drawCursor(), ruler_x, samples_per_column_diskrate, and timer.

BeatGraphLabel::~BeatGraphLabel ( ) [virtual]

References timer.

Member Function Documentation

void BeatGraphLabel::activate ( ) [inline]

Called to start the cursor movements. It will start the timer.

References timer.

void BeatGraphLabel::deactivate ( ) [inline]

Called to stop the cursor movements. It stops the timer.

References timer.

void BeatGraphLabel::drawCueText ( ) [protected]

Will draw the different cues on the resized image

References cue_metarate, cues_metarate, i, metarate_to_diskrate(), original, resized, and samples_per_column_diskrate.

void BeatGraphLabel::drawCursor ( ) [virtual, slot]

will move the ruler with moveruler() and then decide which areas must be repainted. If the old and new ruler were close to each other, one repaint event is scheduler. If not two different repaints are called for.

References moveRuler(), repaint(), and resized.

Referenced by BeatGraphLabel().

void BeatGraphLabel::moveRuler	(	int &	x1,
		int &	x2,
		int &	x3,
		int &	x4
	)			`[protected]`

Will move the ruler and report back (through the 4 output parameters) which columns must be redrawn.

References resized, ruler_x, samples_per_column_diskrate, and x_diskrate.

Referenced by drawCursor(), and paintEvent().

void BeatGraphLabel::paintEvent ( QPaintEvent * e ) [protected, virtual]

If there is no image set, an empty area is drawn. If the cues changed a total redraw is required, otherwise the required areas are copied from the resized image onto the widget.

References cues_changed, moveRuler(), original, resized, samples_per_column_diskrate, and setImage().

void BeatGraphLabel::resizeEvent ( QResizeEvent * event ) [protected, virtual]

When a resize of the widget occur, we recalculate the resized image and redraw the cursor

References cues_changed.

virtual void BeatGraphLabel::setImage	(	QImage	I,
		wunsigned8	samplespercol
	)			`[virtual, slot]`

once the QPixMap is set it remains the property of the label

Referenced by paintEvent().

Member Data Documentation

bool BeatGraphLabel::cues_changed

Referenced by BeatGraphLabel(), paintEvent(), and resizeEvent().

QImage BeatGraphLabel::original [protected]

The original image as produced in the beatgraph analyzer is placed here. Depending on the size of the target window, we resize it to something smaller/or larger.

Referenced by drawCueText(), and paintEvent().

QImage BeatGraphLabel::resized [protected]

The resized image which fits the width() and height() of the widget perfectly.

Referenced by drawCueText(), drawCursor(), moveRuler(), and paintEvent().

int BeatGraphLabel::ruler_x [protected]

The current ruler position; expressed in the internal image coordinates

Referenced by BeatGraphLabel(), and moveRuler().

unsigned8 BeatGraphLabel::samples_per_column_diskrate

Remembers how many audio samples are in one measure. This makes it possible to calculate the current measure based on the current songposition x

Referenced by BeatGraphLabel(), drawCueText(), moveRuler(), and paintEvent().

QTimer BeatGraphLabel::timer

The timer used to update the image if necessary. This timer will be connected to the drawCursor slot.