Source

wxPython / demo / ScrolledWindow.py


import  wx
import  images

# There are two different approaches to drawing, buffered or direct.
# This sample shows both approaches so you can easily compare and
# contrast the two by changing this value.
BUFFERED = 1

#---------------------------------------------------------------------------

class MyCanvas(wx.ScrolledWindow):
    def __init__(self, parent, id = -1, size = wx.DefaultSize):
        wx.ScrolledWindow.__init__(self, parent, id, (0, 0), size=size, style=wx.SUNKEN_BORDER)

        self.lines = []
        self.maxWidth  = 1000
        self.maxHeight = 1000
        self.x = self.y = 0
        self.curLine = []
        self.drawing = False

        self.SetBackgroundColour("WHITE")
        self.SetCursor(wx.StockCursor(wx.CURSOR_PENCIL))
        bmp = images.Test2.GetBitmap()
        mask = wx.Mask(bmp, wx.BLUE)
        bmp.SetMask(mask)
        self.bmp = bmp

        self.SetVirtualSize((self.maxWidth, self.maxHeight))
        self.SetScrollRate(20,20)

        if BUFFERED:
            # Initialize the buffer bitmap.  No real DC is needed at this point.
            self.buffer = wx.EmptyBitmap(self.maxWidth, self.maxHeight)
            dc = wx.BufferedDC(None, self.buffer)
            dc.SetBackground(wx.Brush(self.GetBackgroundColour()))
            dc.Clear()
            self.DoDrawing(dc)

        self.Bind(wx.EVT_LEFT_DOWN, self.OnLeftButtonEvent)
        self.Bind(wx.EVT_LEFT_UP,   self.OnLeftButtonEvent)
        self.Bind(wx.EVT_MOTION,    self.OnLeftButtonEvent)
        self.Bind(wx.EVT_PAINT, self.OnPaint)


    def getWidth(self):
        return self.maxWidth

    def getHeight(self):
        return self.maxHeight


    def OnPaint(self, event):
        if BUFFERED:
            # Create a buffered paint DC.  It will create the real
            # wx.PaintDC and then blit the bitmap to it when dc is
            # deleted.  Since we don't need to draw anything else
            # here that's all there is to it.
            dc = wx.BufferedPaintDC(self, self.buffer, wx.BUFFER_VIRTUAL_AREA)
        else:
            dc = wx.PaintDC(self)
            self.PrepareDC(dc)
            # Since we're not buffering in this case, we have to
            # (re)paint the all the contents of the window, which can
            # be potentially time consuming and flickery depending on
            # what is being drawn and how much of it there is.
            self.DoDrawing(dc)


    def DoDrawing(self, dc, printing=False):
        dc.BeginDrawing()
        dc.SetPen(wx.Pen('RED'))
        dc.DrawRectangle(5, 5, 50, 50)

        dc.SetBrush(wx.LIGHT_GREY_BRUSH)
        dc.SetPen(wx.Pen('BLUE', 4))
        dc.DrawRectangle(15, 15, 50, 50)

        dc.SetFont(wx.Font(14, wx.SWISS, wx.NORMAL, wx.NORMAL))
        dc.SetTextForeground(wx.Colour(0xFF, 0x20, 0xFF))
        te = dc.GetTextExtent("Hello World")
        dc.DrawText("Hello World", 60, 65)

        dc.SetPen(wx.Pen('VIOLET', 4))
        dc.DrawLine(5, 65+te[1], 60+te[0], 65+te[1])

        lst = [(100,110), (150,110), (150,160), (100,160)]
        dc.DrawLines(lst, -60)
        dc.SetPen(wx.GREY_PEN)
        dc.DrawPolygon(lst, 75)
        dc.SetPen(wx.GREEN_PEN)
        dc.DrawSpline(lst+[(100,100)])

        dc.DrawBitmap(self.bmp, 200, 20, True)
        dc.SetTextForeground(wx.Colour(0, 0xFF, 0x80))
        dc.DrawText("a bitmap", 200, 85)

        font = wx.Font(20, wx.SWISS, wx.NORMAL, wx.NORMAL)
        dc.SetFont(font)
        dc.SetTextForeground(wx.BLACK)

        for a in range(0, 360, 45):
            dc.DrawRotatedText("Rotated text...", 300, 300, a)

        dc.SetPen(wx.TRANSPARENT_PEN)
        dc.SetBrush(wx.BLUE_BRUSH)
        dc.DrawRectangle(50,500, 50,50)
        dc.DrawRectangle(100,500, 50,50)

        dc.SetPen(wx.Pen('RED'))
        dc.DrawEllipticArc(200,500, 50,75, 0, 90)

        if not printing:
            # This has troubles when used on a print preview in wxGTK,
            # probably something to do with the pen styles and the scaling
            # it does...
            y = 20

            for style in [wx.DOT, wx.LONG_DASH, wx.SHORT_DASH, wx.DOT_DASH, wx.USER_DASH]:
                pen = wx.Pen("DARK ORCHID", 1, style)
                if style == wx.USER_DASH:
                    pen.SetCap(wx.CAP_BUTT)
                    pen.SetDashes([1,2])
                    pen.SetColour("RED")
                dc.SetPen(pen)
                dc.DrawLine(300,y, 400,y)
                y = y + 10

        dc.SetBrush(wx.TRANSPARENT_BRUSH)
        dc.SetPen(wx.Pen(wx.Colour(0xFF, 0x20, 0xFF), 1, wx.SOLID))
        dc.DrawRectangle(450,50,  100,100)
        old_pen = dc.GetPen()
        new_pen = wx.Pen("BLACK", 5)
        dc.SetPen(new_pen)
        dc.DrawRectangle(470,70,  60,60)
        dc.SetPen(old_pen)
        dc.DrawRectangle(490,90, 20,20)

        dc.GradientFillLinear((20, 260, 50, 50),
                              "red", "blue")
        dc.GradientFillConcentric((20, 325, 50, 50),
                                  "red", "blue", (25,25))
        self.DrawSavedLines(dc)
        dc.EndDrawing()


    def DrawSavedLines(self, dc):
        dc.SetPen(wx.Pen('MEDIUM FOREST GREEN', 4))

        for line in self.lines:
            for coords in line:
                apply(dc.DrawLine, coords)


    def SetXY(self, event):
        self.x, self.y = self.ConvertEventCoords(event)

    def ConvertEventCoords(self, event):
        newpos = self.CalcUnscrolledPosition(event.GetX(), event.GetY())
        return newpos

    def OnLeftButtonEvent(self, event):
        if event.LeftDown():
            self.SetFocus()
            self.SetXY(event)
            self.curLine = []
            self.CaptureMouse()
            self.drawing = True

        elif event.Dragging() and self.drawing:
            if BUFFERED:
                # If doing buffered drawing we'll just update the
                # buffer here and then refresh that portion of the
                # window.  Then the system will send an event and that
                # portion of the buffer will be redrawn in the
                # EVT_PAINT handler.
                dc = wx.BufferedDC(None, self.buffer)
            else:
                # otherwise we'll draw directly to a wx.ClientDC
                dc = wx.ClientDC(self)
                self.PrepareDC(dc)

            dc.SetPen(wx.Pen('MEDIUM FOREST GREEN', 4))
            coords = (self.x, self.y) + self.ConvertEventCoords(event)
            self.curLine.append(coords)
            dc.DrawLine(*coords)
            self.SetXY(event)
            
            if BUFFERED:
                # figure out what part of the window to refresh, based
                # on what parts of the buffer we just updated
                x1,y1, x2,y2 = dc.GetBoundingBox()
                x1,y1 = self.CalcScrolledPosition(x1, y1)
                x2,y2 = self.CalcScrolledPosition(x2, y2)
                # make a rectangle
                rect = wx.Rect()
                rect.SetTopLeft((x1,y1))
                rect.SetBottomRight((x2,y2))
                rect.Inflate(2,2)
                # refresh it
                self.RefreshRect(rect)

        elif event.LeftUp() and self.drawing:
            self.lines.append(self.curLine)
            self.curLine = []
            self.ReleaseMouse()
            self.drawing = False


## This is an example of what to do for the EVT_MOUSEWHEEL event,
## but since wx.ScrolledWindow does this already it's not
## necessary to do it ourselves. You would need to add an event table 
## entry to __init__() to direct wheelmouse events to this handler.

##     wheelScroll = 0
##     def OnWheel(self, evt):
##         delta = evt.GetWheelDelta()
##         rot = evt.GetWheelRotation()
##         linesPer = evt.GetLinesPerAction()
##         print delta, rot, linesPer
##         ws = self.wheelScroll
##         ws = ws + rot
##         lines = ws / delta
##         ws = ws - lines * delta
##         self.wheelScroll = ws
##         if lines != 0:
##             lines = lines * linesPer
##             vsx, vsy = self.GetViewStart()
##             scrollTo = vsy - lines
##             self.Scroll(-1, scrollTo)

#---------------------------------------------------------------------------

def runTest(frame, nb, log):
    win = MyCanvas(nb)
    return win

#---------------------------------------------------------------------------



overview = """
<html>
<body>
The wx.ScrolledWindow class manages scrolling for its client area, transforming the 
coordinates according to the scrollbar positions, and setting the scroll positions, 
thumb sizes and ranges according to the area in view.
</body>
</html>
"""


if __name__ == '__main__':
    import sys,os
    import run
    run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])