#!/usr/bin/env python import wx g = wx import wx.lib.scrolledpanel as scrolled # To test compatibility of gradients with the generic GraphicsContext classes # uncomment this line #import wx.lib.graphics as g #---------------------------------------------------------------------- class GradientPanel(wx.Panel): """ This panel will be painted with the gradient brush created by the rest of the sample. """ def __init__(self, parent): wx.Panel.__init__(self, parent, -1) # Create a simple default brush we can use until a gradient # brush is given to us self.brush = wx.WHITE_BRUSH self.SetBackgroundStyle(wx.BG_STYLE_PAINT) self.Bind(wx.EVT_PAINT, self.OnPaint) self.SetInitialSize((600,100)) def DrawWithBrush(self, brush): self.brush = brush self.Refresh() def OnPaint(self, evt): dc = wx.PaintDC(self) gc = g.GraphicsContext.Create(dc) gc.SetBrush(self.brush) gc.SetPen(wx.Pen('black', 1)) w, h = gc.GetSize() gc.DrawRectangle(0,0,w,h) class GradientStopPanel(wx.Panel): """ Contains the controls for editing each gradient stop. (Colour, alpha and relative position.) """ def __init__(self, parent, posVal, colour=wx.BLACK, alpha=wx.ALPHA_OPAQUE): wx.Panel.__init__(self, parent) # make some widgets self.pos = wx.SpinCtrlDouble(self, value='%2f' % posVal, size=(65,-1), min=0.0, max=1.0, initial=posVal, inc=0.01) self.pos.SetToolTip( "A value between 0 and 1 representing the distance between (x1,y1) " "and (x2,y2) for this gradient stop.") self.clrPicker = wx.ColourPickerCtrl(self, colour=colour) self.clrPicker.SetToolTip("The colour for this gradient stop") self.minusBtn = wx.Button(self, -1, " - ", style=wx.BU_EXACTFIT) self.minusBtn.SetToolTip("Remove this gradient stop") # put them in a sizer sizer = wx.BoxSizer(wx.HORIZONTAL) sizer.Add(self.pos, 0, wx.ALIGN_CENTER_VERTICAL) sizer.Add(self.clrPicker, 0, wx.ALIGN_CENTER_VERTICAL|wx.LEFT, 10) sizer.Add(self.minusBtn, 0, wx.ALIGN_CENTER_VERTICAL|wx.LEFT, 25) border = wx.BoxSizer() border.Add(sizer, 1, wx.EXPAND|wx.ALL, 4) self.SetSizer(border) self.Bind(wx.EVT_BUTTON, self.OnMinusButton, self.minusBtn) @property def colour(self): return self.clrPicker.GetColour() @property def position(self): return self.pos.GetValue() def OnMinusButton(self, evt): wx.CallAfter(self.Parent.RemoveStop, self) class TestPanel(scrolled.ScrolledPanel): """ The main panel for this sample """ def __init__(self, parent, log): self.log = log scrolled.ScrolledPanel.__init__(self, parent, -1) # make the panel that will display the gradient self.gpanel = GradientPanel(self) # and the other widgets for collecting data about the gradient label1 = wx.StaticText(self, -1, "Geometry") label1.SetFont(wx.FFont(15, wx.FONTFAMILY_SWISS, wx.FONTFLAG_BOLD)) x1 = 0 x2 = self.gpanel.Size.width y0 = self.gpanel.Size.height / 2 self.x1 = wx.TextCtrl(self, value=str(x1), size=(50,-1)) self.y1 = wx.TextCtrl(self, value=str(y0), size=(50,-1)) self.x2 = wx.TextCtrl(self, value=str(x2), size=(50,-1)) self.y2 = wx.TextCtrl(self, value=str(y0), size=(50,-1)) label2 = wx.StaticText(self, -1, "Stops") label2.SetFont(wx.FFont(15, wx.FONTFAMILY_SWISS, wx.FONTFLAG_BOLD)) firstStop = GradientStopPanel(self, 0.0) lastStop = GradientStopPanel(self, 1.0, wx.WHITE) self.stops = [firstStop, lastStop] addStopBtn = wx.Button(self, -1, " + ", style=wx.BU_EXACTFIT) # bind some events self.Bind(wx.EVT_BUTTON, self.OnAddStop, addStopBtn) self.Bind(wx.EVT_SPINCTRLDOUBLE, self.OnPositionUpdated) self.Bind(wx.EVT_COLOURPICKER_CHANGED, self.OnColourChanged) self.Bind(wx.EVT_TEXT, self.OnGeometryChanged) # do the layout sizer = wx.BoxSizer(wx.VERTICAL) sizer.Add(self.gpanel) sizer.Add((1,15)) sizer.Add(label1) sizer.Add((1, 5)) fgs = wx.FlexGridSizer(cols=11, hgap=5, vgap=5) fgs.AddMany([ (wx.StaticText(self, -1, "x1:"), 0, wx.ALIGN_CENTER_VERTICAL), self.x1, ((5,1)), (wx.StaticText(self, -1, "y1:"), 0, wx.ALIGN_CENTER_VERTICAL), self.y1] ) fgs.Add((40,1)) fgs.AddMany([ (wx.StaticText(self, -1, "x2:"), 0, wx.ALIGN_CENTER_VERTICAL), self.x2, ((5,1)), (wx.StaticText(self, -1, "y2:"), 0, wx.ALIGN_CENTER_VERTICAL), self.y2] ) sizer.Add(fgs, 0, wx.LEFT, 25) sizer.Add((1,15)) sizer.Add(label2) sizer.Add((1, 5)) self.stopSizer = wx.BoxSizer(wx.VERTICAL) self.stopSizer.Add(firstStop) self.stopSizer.Add(lastStop) self.stopSizer.Add(addStopBtn, 0, wx.TOP, 10) sizer.Add(self.stopSizer, 0, wx.LEFT, 25) border = wx.BoxSizer() border.Add(sizer, 1, wx.EXPAND|wx.ALL, 15) self.SetSizer(border) self.SetLimits() self.UpdateBrush() self.SetupScrolling() def RemoveStop(self, stop): self.stops.remove(stop) stop.Destroy() self.Layout() self.SetLimits() self.UpdateBrush() self.SetupScrolling() def OnAddStop(self, evt): newstop = GradientStopPanel(self, 1.0) self.stopSizer.Insert(len(self.stops), newstop) self.stops.append(newstop) self.Layout() self.SetLimits() self.UpdateBrush() self.SetupScrolling() def OnPositionUpdated(self, evt): # called when any of the spinctrls in the nested panels are updated self.SetLimits() self.UpdateBrush() def OnColourChanged(self, evt): # called when any of the color pickers are updated self.UpdateBrush() def OnGeometryChanged(self, evt): # called for changes to x1,y1 or x2,y2 self.UpdateBrush() def SetLimits(self): # Tweak the panels in self.stops to set limits on the allowed # positions, and to disable those that should not be changed or # removed. first = self.stops[0] last = self.stops[-1] first.pos.Disable() first.minusBtn.Disable() last.pos.Disable() last.minusBtn.Disable() for idx in range(1, len(self.stops)-1): prev = self.stops[idx-1] next = self.stops[idx+1] stop = self.stops[idx] stop.pos.SetMin(prev.position) stop.pos.SetMax(next.position) stop.pos.Enable() stop.minusBtn.Enable() def UpdateBrush(self): """ This is where the magic happens. We convert all the values from the widgets on this panel into a collection of gradient stops and then create a brush from them, and finally, ask the display panel to repaint itself with that new brush. """ def floatOrZero(value): try: return float(value) except ValueError: return 0.0 x1 = floatOrZero(self.x1.Value) y1 = floatOrZero(self.y1.Value) x2 = floatOrZero(self.x2.Value) y2 = floatOrZero(self.y2.Value) gstops = g.GraphicsGradientStops() gstops.SetStartColour(self.stops[0].colour) gstops.SetEndColour(self.stops[-1].colour) for s in self.stops[1:-1]: gs = g.GraphicsGradientStop(s.colour, s.position) gstops.Add(gs) ctx = g.GraphicsContext.Create() brush = ctx.CreateLinearGradientBrush(x1,y1, x2,y2, gstops) self.gpanel.DrawWithBrush(brush) #---------------------------------------------------------------------- def runTest(frame, nb, log): win = TestPanel(nb, log) return win #---------------------------------------------------------------------- overview = """

Gradients on a GraphicsContext

Multi-stop gradients can be used as fills in a wx.GraphicsContext. This sample shows how to use the GraphicsGradientStops class to accomplish this and allows the user to experiment with gradients. """ if __name__ == '__main__': import sys,os import run run.main(['', os.path.basename(sys.argv[0])] + sys.argv[1:])