scale painter to fit my widget

[jesse_mark]

Thanks , this is what i was looking for.
but now im facing other problem, which is the size.

for example,

I want to draw an ellipce in the same area.

i want the postion of the ellipce to be affected and to be mapped to viewport area. but i want it to keep the same size i assinge to it.

for example :

Painter.drawEllpice(x,y,2,2);
now when i map it to the viewPort, and when the x,y are really big, you can not see the ellipce at all and as size is mapped as well and beome sooo small.

so is there a way to can keep the size always the same no matter what x,y is or no matter what viewport i gave.

Thanks

[wysota]

Did you use setWindow?

[jesse_mark]

yes I did.

this is wat i did:
Qrect my rect(x,y,h,w);
QPoint p(x1,y1);

painter.setViewPort(widget->rect());
painter.setwindow(x,y,h,w);


painter.drawRect(myrect);
painter.drawEllipce(p,2,2);


is my rect is small , the ellipce is fine, but if the rect is big and then the ellipce is sooo samll that u cannot see
i have to set the size of the ellipce so big so i can see it.

like:
painter.drawEllipce(p,2000,2000);

but ofcource then is the window is small the ellipce will be too big.

[wysota]

What did you pass as x, y, h and w? (btw. it is w and h and not h and w)

[jesse_mark]

i passed the value of my rect:

for example :

QRect myrect(0,0,2000,4000);
QPoint(1000,2000);
 
QRect veiwRect = widget->rect();
 
 
painter.setViewPort(viewRect)
painter.setWindow(myRect);
 
painter.drawRect(myRect);

QRect myrect(0,0,2000,4000);
QPoint(1000,2000);

QRect veiwRect = widget->rect();


painter.setViewPort(viewRect)
painter.setWindow(myRect);

painter.drawRect(myRect);

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I notice something else is that, it will fill the whole widget and it will not use its a coordinates, so even if was the height a way bigger than the width,
it still show that the width bigger than the height.

[wysota]

If you pass such big values then no wonder your ellipse is so small. 2 / 2000 = 0.001; 2 / 4000 = 0.0005 so your ellipse takes 0.1% x 0.05% of the widget area.

[jesse_mark]

yeah i know, so this is why im asking if there is a way to make the size of the ellipce fixed, because the rect some times have big values and other may have small value.

so im asking if there is a way to make the ellipce has fixed size and will be showen with same size all the times.

[wysota]

yeah i know, so this is why im asking if there is a way to make the size of the ellipce fixed

Draw the ellipse before you use setWindow() and setViewport() or pass invalid rects to the two to reset them to default before painting the ellipse.

[jesse_mark]

the issue is that the ellipse position then.
where the position of the ellipse is related to the rect i draw.
if i do it before or pass empty rects, the shot will be drawn out side of the visible area of the widget.

[wysota]

I'm sorry, I do not understand what you want. Unless you manage to explain it better, I'm afraid I can't help you.

[jesse_mark]

OK, ill try to explain what im trying to do exactly,

I have a small widget, lets say it with size of 250, 250.

I want to draw a rectangle and an ellipse.

the rect can be really big or small depend on the user input. and the ellipse position as well.
i want them to be scaled to fit in the widget.

ps: the ellipse position will be really close to the rect, so it could be beside one of the rect borders or in the middle of the rect.

[wysota]

It is still not clear what you want. For me "scaled to fit" means the ellipse and rectangle should be the size of the widget:

void Widget::paintEvent(QPaintEvent *pe) {
  QPainter p(this);
  p.setBrush(Qt::red);
  p.drawRect(rect());
  p.setBrush(Qt::yellow);
  p.drawEllipse(rect());
}

void Widget::paintEvent(QPaintEvent *pe) {
  QPainter p(this);
  p.setBrush(Qt::red);
  p.drawRect(rect());
  p.setBrush(Qt::yellow);
  p.drawEllipse(rect());
}

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If you wish to keep the aspect ratio then compare width to height and scale the rectangle to the smaller of the two values.

int side = qMin(width(), height());
QRect r(0,0, side, side);
r.moveCenter(rect().center());
p.drawRect(r);
p.drawEllipse(r);

int side = qMin(width(), height());
QRect r(0,0, side, side);
r.moveCenter(rect().center());
p.drawRect(r);
p.drawEllipse(r);

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