Develop Reference

QGraphicsPathItem different colors

Is there a way to get 2 different fill colors for a single QGraphicsPathItem object?
For example:
# Try to get a white text onto a grey rectangle
itemPath = QtGui.QPainterPath()
itemPath.setFillRule(QtCore.Qt.WindingFill)
self.setBrush( QtGui.QColor(100, 100, 100) )
itemPath.addRect(-10, -60, 150, 70)
itemFont = QtGui.QFont()
itemFont.setPointSize(50)
self.setBrush( QtGui.QColor(255, 255, 255) )
itemPath.addText(0, 0, itemFont, txt)
Right now it's just using the last brush color for the rectangle and text. I'd like to color them differently though, but still as the same QGraphicsPathItem. Or better yet, a way to give the text a background so it's easier to select.
Update
Here's an example. I want a white text with a red background, but I only get the last used brush color.
from PySide import QtGui, QtCore
class TextItem(QtGui.QGraphicsPathItem):
def __init__(self):
super(TextItem, self).__init__()
itemPath = QtGui.QPainterPath()
itemPath.setFillRule(QtCore.Qt.WindingFill)
# Create rectangle with red color
self.setBrush( QtGui.QColor(255, 0, 0) )
itemPath.addRect(-10, -50, 130, 60)
self.setPath(itemPath)
# Create text with white color
itemFont = QtGui.QFont()
itemFont.setPointSize(40)
self.setBrush( QtGui.QColor(255, 255, 255) )
itemPath.addText(0, 0, itemFont, 'Test!')
self.setPath(itemPath)
self.moveBy(100, 100)
class Window(QtGui.QWidget):
def __init__(self):
super(Window, self).__init__()
self.resize(500, 500)
self.view = QtGui.QGraphicsView(self)
self.view.setScene( QtGui.QGraphicsScene(self) )
self.view.setSceneRect( 0, 0, 500, 500 )
self.view.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)
self.view.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)
mainLayout = QtGui.QVBoxLayout()
mainLayout.addWidget(self.view)
self.setLayout(mainLayout)
newItem = TextItem()
self.view.scene().addItem( newItem )
def run(self):
self.show()
win = Window()
win.show()

The problem is that your first self.setPath and self.setBrush calls are just over-ridden by the second ones. These properties of the QGraphicsPathItem are not used until you get to the paint event. So the first settings do nothing and the values left in these properties after the initialisation are the ones used to paint the item.
It's not too difficult to do what you want but you have quite a lot of options, and you need to choose based on other aspects of your design.
The simplest option would be to just create a QGraphicsRectItem and then give it a QGraphicsSimpleTextItem child. This is particularly simple in that you wouldn't even need to create a subclass of your own: simply create the instances, set their Paths and Brushes and use them directly. I strongly recommend this approach if it does what you neeed.
rectItem = QtGui.QGraphicsRectItem(0, 0, 130, 60)
rectItem.setBrush(QtGui.QColor(255, 0, 0))
textItem = QtGui.QGraphicsSimpleTextItem("Test!",rectItem)
itemFont = QtGui.QFont()
itemFont.setPointSize(40)
textItem.setBrush( QtGui.QColor(200, 200, 200) )
textItem.setFont(itemFont)
textItem.setPos(10,0)
self.view.scene().addItem( rectItem )
rectItem.moveBy(100,100)
Another simple option would be just create the two items and then add them into a QGraphicsItemGroup. This makes sense if you might want to separate the items or work with them separately.
rectItem = QtGui.QGraphicsRectItem(0, 0, 130, 60)
rectItem.setBrush(QtGui.QColor(255, 0, 0))
self.view.scene().addItem( rectItem )
textItem = QtGui.QGraphicsSimpleTextItem("Test!")
itemFont = QtGui.QFont()
itemFont.setPointSize(40)
textItem.setBrush( QtGui.QColor(200, 200, 200) )
textItem.setFont(itemFont)
textItem.setPos(10,0)
self.view.scene().addItem( textItem )
group = QtGui.QGraphicsItemGroup()
group.addToGroup(rectItem)
group.addToGroup(textItem)
group.moveBy(100,100)
self.view.scene().addItem( group )
If you need to create a class of your own for other reasons then you have quite a few options. The most general will be to subclass QGraphicsItem. You can create a MyTextItem with, for example, two Paths and two Brushes, and use them both when you paint the Item. You will have to implement boundingRect and paint but in this case both will be quite easy. This is probably a good way to go if you foresee adding lots of additional functionality to the item.
Other options would be to subclass QRectItem and add a text path to it. Again you will need to re-implement paint, but that might be all that was needed. Or you could subclass QSimpleTextItem and add a rect to it.

How do I stop paintEvent from painting children widgets?

I'm trying to add rounded corners to a QDialog. I'm defining my own paintEvent method to create rounded corners. It's working, but it's adding rounded borders to everything. Even the cursor is getting a border. Is there any way to disable this behavior?
Example code:
from PySide import QtCore, QtGui
class RenameDialog(QtGui.QDialog):
def __init__(self, parent=None, **kwargs):
super(RenameDialog, self).__init__(
parent=parent, f=QtCore.Qt.CustomizeWindowHint)
self.fieldA = QtGui.QLineEdit(self)
self.fieldB = QtGui.QLineEdit(self)
self.setLayout(QtGui.QHBoxLayout())
self.layout().addWidget(self.fieldA)
self.layout().addWidget(self.fieldB)
# Set background transparent. Only items drawn in paintEvent
# will be visible.
palette = QtGui.QPalette()
palette.setColor(QtGui.QPalette.Base, QtCore.Qt.transparent)
self.setAttribute(QtCore.Qt.WA_TranslucentBackground, True)
self.setPalette(palette)
def paintEvent(self, event):
painter = QtGui.QPainter(self)
fillColor = QtGui.QColor(75, 75, 75, 255)
lineColor = QtCore.Qt.gray
painter.setRenderHint(QtGui.QPainter.Antialiasing)
painter.setPen(QtGui.QPen(QtGui.QBrush(lineColor), 2.0))
painter.setBrush(QtGui.QBrush(fillColor))
painter.drawRoundedRect(event.rect(), 15, 15)
I'm trying to do this with a paintEvent because:
QDialog stylesheets cannot use border-radius. Curved borders do show up, but corners are still visible.
QDialogs.setMask() works, but there is no way (that I know of) to anti-alias the mask.
Here is what that looks like:

Paint events are sent to a window/widget with the precise rectangle that needs updating not the whole bounding rectangle of the widget. When you call event.rect() it returns the rectangle that needs updating (As far as I know)
Try changing this line
painter.drawRoundedRect(event.rect(), 15, 15)
To this
painter.drawRoundedRect(self.rect(), 15, 15)
EDIT:
You also need to add this line anywhere in the constructor
self.setWindowFlags(QtCore.Qt.FramelessWindowHint)
Hope this helps.

I've found a work-around for now. You can hide the extra borders by using QPainter.eraseRect on the children and having the correct stylesheet set. I've also found that painting over the offending area with QPainter.fillRect works too.
def paintEvent(self, event):
painter = QtGui.QPainter(self)
fillColor = QtGui.QColor(75, 75, 75, 255)
lineColor = QtCore.Qt.gray
painter.setRenderHint(QtGui.QPainter.Antialiasing)
painter.setPen(QtGui.QPen(QtGui.QBrush(lineColor), 2.0))
painter.setBrush(QtGui.QBrush(fillColor))
painter.drawRoundedRect(event.rect(), 15, 15)
# Sketchy fix:
painter.eraseRect(self.childrenRect())
# OR
painter.fillRect(self.childrenRect(), QtGui.QBrush(fillColor))
This doesn't answer my original question though. I'd like to avoid this behavior rather than masking it. So I'm not going to mark this as the answer.

draw an image to gtk.DrawingArea?

I'm writing a PyGtk paint program based on the basic tutorial found here.
Is there any way to add an image to the drawing area so that you can still draw over the image? Like a stamp, or an imported photo for example. I've tried adding a gtk.Image() but gtk.DrawingArea object has no attribute add.
self.window = gtk.Window((gtk.WINDOW_TOPLEVEL))
self.window.set_title ("Canvas")
self.window.set_position(gtk.WIN_POS_CENTER)
hbox = gtk.HBox(False, 0)
self.window.add(hbox)
self.window.set_resizable(False)
# Create the drawing area
drawing_area = gtk.DrawingArea()
drawing_area.set_size_request(screenWidth-350, screenHeight-100)
hbox.pack_start(drawing_area, True, True, 0)
drawing_area.show()

You have to draw the image (as a gtk.gdk.Pixbuf, not gtk.Image) onto the backing pixmap yourself using gtk.gdk.Drawable.draw_pixbuf(). Only container widgets (widgets that can contain other widgets) have an add() method, and gtk.DrawingArea is not one.
pixbuf = gtk.gdk.pixbuf_new_from_file(image_filename) #one way to load a pixbuf
pixmap.draw_pixbuf(None, pixbuf, 0, 0, x, y, -1, -1, gtk.gdk.RGB_DITHER_NONE, 0, 0)

PySide Error - QPaintDevice: Cannot destroy paint device that is being painted

I'm baffled by this one. I tried moving the QPainter to it's own def as some have suggested, but it gives the exact same error. Here's the def I created.
def PaintButtons(self):
solid = QtGui.QPixmap(200, 32)
paint = QtGui.QPainter()
paint.begin(solid)
paint.setPen(QtGui.Qcolor(255,255,255))
paint.setBrush(QtGui.QColor(255, 0, 0))
paint.drawRect(0, 0, 200, 32)
paint.end()

It was just a typo. You're using Qcolor (the first occurrence).Changing that to QColor will do the trick. :)

Why is this code not accepting this png images transparency?

I've isolated the cause of the problem to be the image, since the code seems to work with other png images with transparency. However, it doesn't seem to work with the one image I need it to. This would be of great help seeing as I'm trying to make a nice shaped window.
The image:
The code:
import wx
class PictureWindow(wx.Frame):
def __init__(self, parent, id, title, pic_location):
# For PNGs. Must be PNG-8 for transparency...
self.bmp = wx.Image(pic_location, wx.BITMAP_TYPE_PNG).ConvertToBitmap()
framesize = (self.bmp.GetWidth(), self.bmp.GetHeight())
# Launch a frame the size of our image. Note the position and style stuff...
# (Set pos to (-1, -1) to let the OS place it.
# This style wx.FRAME_SHAPED is a frameless plain window.
wx.Frame.__init__(self, parent, id, title, size=framesize, pos = (50, 50), style = wx.FRAME_SHAPED)
r = wx.RegionFromBitmap(self.bmp)
self.SetShape(r)
# Define the panel and place the pic
panel = wx.Panel(self, -1)
self.mainPic = wx.StaticBitmap(panel, -1, self.bmp)
# Set an icon for the window if we'd like
#icon1 = wx.Icon("icon.ico", wx.BITMAP_TYPE_ICO)
#self.SetIcon(icon1)
self.Show()
# The paint stuff is only necessary if doing a shaped window
self.Bind(wx.EVT_PAINT, self.OnPaint)
self.Main()
def OnPaint(self, event):
dc = wx.PaintDC(self)
dc.DrawBitmap(self.bmp, 0, 0, True)
def Main(self):
sizer = wx.GridBagSizer()
button = wx.Button(self,-1,label="Click me !")
sizer.Add(button, (0,1))
# What pic are we opening?
pic_location = r"C:\Users\user\Pictures\CPUBAR\A4.png" # PNG must be png-8 for transparency...
app = wx.App(redirect=0) # the redirect parameter keeps stdout from opening a wx gui window
PictureWindow(None, -1, 'Picture Viewer', pic_location)
app.MainLoop()
This is in Windows 7, btw.

wx.RegionFromBitmap uses the bitmap's mask to set the shape. If your source image has an alpha channel then it won't have a mask and so wx.RegionFromBitmap will not be able to determine what shape to use. You can convert the source image such that all pixels are either fully opaque or fully transparent, and then wx.Image will load it with a mask instead of an alpha channel. Or you can convert it at runtime using wx.Image's ConvertAlphaToMask method before converting it to a wx.Bitmap.

Your code says that it needs to be in png-8 format in order for transparency to work.
First of all, is the image in png-8 format?
second, why is this a requisite for transparency???

You're converting your image to a bitmap - bitmaps do not support transparency.

As a workaround you could use a .gif (if you can stand the limited color set).
They only support a 1-bit alpha channel.