Hi Boudewijn Rempt,
I think my solution will be useful for future users of Calligra's
components. This is what I came up with, and this is working as
expected: cells that had no background info set become transparent,
cells that have background info set retain that background as
non-transparent (this is my expected result). I guess opacity setting
could still be used (while painting or globally) in case somebody wants
cells with background info set to be semi-transparent (but for my
use-case this isn't the case). I would o could have decorated painter
instead of writing to the original, and then passing my decorated one to
super's method, but it looks like QPainter has no copy constructor. And
I think that if I just restore painter that it'll all be fine too.
My solution:
myfile.h
class MyGraphicsItem: public QGraphicsRectItem
{
public:
explicit MyGraphicsItem( const QFileInfo& file, const QRectF& rect,
QGraphicsItem *parent = 0) ;
~MyGraphicsItem();
/*reimp*/ void resize(const QSizeF& size);
void updateFile(const QFileInfo& file);
enum ScaleMode {
ScaleToItem = 0, //scale to the item's size
// AspectRatioScale, //same, keep aspect ratio
NoScale
};
private:
bool m_canvasSet;
Calligra::Sheets::Doc *m_cachedDoc;
Calligra::Sheets::CanvasItem *m_canvas;
Calligra::Sheets::Part *m_part;
MyGraphicsItem::ScaleMode m_scaleMode;
};
class TransparentCanvasItem : public Calligra::Sheets::CanvasItem
{
Q_OBJECT
public:
TransparentCanvasItem(Calligra::Sheets::Doc *doc, QGraphicsItem *parent =
0);
protected:
void paint( QPainter * painter, const QStyleOptionGraphicsItem * option,
QWidget * widget = 0);
};
myfile.cpp
TransparentCanvasItem::TransparentCanvasItem(Doc *doc, QGraphicsItem *parent) :
CanvasItem(doc, parent)
{
}
void TransparentCanvasItem::paint( QPainter * painter, const
QStyleOptionGraphicsItem * option, QWidget * widget)
{
Qt::BGMode origBgMode = painter->backgroundMode();
QBrush brush, origBrush = painter->background();
brush = origBrush;
brush.setColor(Qt::transparent);
painter->setBackgroundMode(Qt::TransparentMode);
painter->setBackground(brush);
CanvasItem::paint(painter, option, widget);
painter->setBackground(origBrush);
painter->setBackgroundMode(origBgMode);
}
MyGraphicsItem::~CalligraItem()
{
if (m_part != 0)
delete m_part;
if (m_canvas != 0)
delete m_canvas;
if (m_cachedDoc != 0)
delete m_cachedDoc;
}
void MyGraphicsItem::resize(const QSizeF& size)
{
QRectF r = rect();
r.setSize(size);
setRect(r);
if (m_canvasSet && m_canvas != 0) {
m_canvas->resetTransform();
switch (m_scaleMode) {
case (MyGraphicsItem::ScaleToItem):
m_canvas->scale(size.width() /
m_canvas->boundingRect().size().width(), size.height() /
m_canvas->boundingRect().size().height());
break;
default:
m_canvas->setGeometry(r);
}
}
}
void MyGraphicsItem::updateFile(const QFileInfo& file)
{
if (!file.isFile())
return;
Part *part = new Part(0);
Doc *doc = new Doc(part);
part->setDocument(doc);
if (!doc->openUrl(KUrl(file.absoluteFilePath()))) {
delete doc;
return;
}
if (m_part != 0)
delete m_part;
if (m_canvas != 0) {
m_canvas->setParentItem(0);
m_canvas->scene()->removeItem(m_canvas);
delete m_canvas;
}
if (m_cachedDoc != 0)
delete m_cachedDoc;
m_cachedDoc = doc;
m_part = part;
m_canvas = new TransparentCanvasItem (doc);
//m_canvas = static_cast<CanvasItem*> (m_part->createCanvasItem());
m_canvas->setParentItem(this);
}
Kind regards,
Philip
On Fri, 2012-11-30 at 14:39 +0100, Boudewijn Rempt wrote:
> On Fri, 30 Nov 2012, Philip Van Hoof wrote:
>
> > Hi there,
> >
> > I'm trying to make the cells of a spreadsheet document which I have
> > loaded using sheets/part/CanvasItem.h, which is a GraphicsItem,
> > transparent.
>
>
> Hm... let's see. The basic painting code is in CanvasBase.cpp, where line
> 477 says
>
> painter->fillRect(paintRect, painter->background());
>
> But where is the background on the QPainter object set... I think we need
> Mek to figure that out. You could hack your version of sheets' canvasbase
> here to something like
>
> Qt::BGMode bgMode = painter->backgroundMode();
> painter->setBackgroundMode(Qt::TransparentMode();
>
> ...
>
> painter->setBackgroundMode(bgMode);
>
> sheet->backgroundImageProperties are something different, I think -- it
> must be meant to show an actual image as specified by the document, like a
> watermark.
>
> QGraphicsItem::setOpacity also isn't what you need, since that would set
> the opacity for everything including the cell foregrounds.
>
> >
> > I tried the following code, but although the result is that the color of
> > all cells changes, the color it uses isn't transparent but white. Or
> > perhaps it is transparent but there is something white behind the cells
> > anyway.
> >
> > QGraphicsRectItem rect;
> >
> > Part *part = new Part(0);
> > Doc *doc = new Doc(part);
> > part->setDocument(doc);
> >
> > CanvasItem *m_canvas = new CanvasItem (doc);
> > m_canvas->setParentItem(&rect);
> >
> > Sheet *sheet = m_canvas->activeSheet();
> >
> > Calligra::Sheets::Region region = Calligra::Sheets::Region(1, 1, KS_colMax,
> > KS_rowMax);
> >
> > Style style;
> > QBrush brush;
> > brush.setColor(Qt::transparent);
> > style.setBackgroundBrush(brush);
> > style.setBackgroundColor(Qt::transparent);
> >
> > Sheet::BackgroundImageProperties props = sheet->backgroundImageProperties();
> > props.opacity = 0;
> > sheet->setBackgroundImageProperties( props );
> >
> > CellStorage *cells = sheet->cellStorage();
> > cells->setStyle(region, style);
> >
> > scene.addItem(&rect);
> >
> > Does somebody know how I can make it be truly transparent? Is there
> > something being drawn behind the CellView instances that is white? Like
> > a background maybe?
> >
> > I noticed the existence of the API sheet->setBackgroundImageProperties.
> > As you can see above I tried using it, but it didn't change much.
> >
> > If I would have to patch Calligra to make this effect possible, where
> > should I start looking?
> >
> > Kind regards,
> >
> > Philip
> >
> >
> >
> > --
> >
> >
> > Philip Van Hoof
> > Software developer
> > Codeminded BVBA - http://codeminded.be
> >
> > _______________________________________________
> > calligra-devel mailing list
> > calligra-devel@kde.org
> > https://mail.kde.org/mailman/listinfo/calligra-devel
> >
> _______________________________________________
> calligra-devel mailing list
> calligra-devel@kde.org
> https://mail.kde.org/mailman/listinfo/calligra-devel
>
--
Philip Van Hoof
Software developer
Codeminded BVBA - http://codeminded.be
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