Fix aspect ratio of logo image so it is not stretched or squashed (#376)

Also add two new tests that make sure logo stays the right aspect
ratio whether the canvas is tall/narrow or short/wide.

tests/test_vcs_draw_logo_on.py

@@ -14,3 +14,17 @@ def testDrawLogoOn(self):
  self.x.plot(a, bg=self.bg)
  fnm = "test_vcs_draw_logo_on.png"
  self.checkImage(fnm)
+
+ self.x.clear()
+ self.x.drawlogoon()
+ self.x.geometry(800, 400)
+ self.x.plot(a, bg=self.bg)
+ fnm = "test_vcs_draw_logo_on_wide.png"
+ self.checkImage(fnm)
+
+ self.x.clear()
+ self.x.drawlogoon()
+ self.x.geometry(400, 800)
+ self.x.plot(a, bg=self.bg)
+ fnm = "test_vcs_draw_logo_on_tall.png"
+ self.checkImage(fnm)

vcs/VTKPlots.py

@@ -215,6 +215,7 @@ def __init__(self, canvas, renWin=None,
  self.plotRenderers = set()
  # Maps priorities to renderers
  self.text_renderers = {}
+ self.logoContextArea = None
  self.logoContextItem = None
  self.logoContextItemPython = None
  self.renderer = None
@@ -576,6 +577,14 @@ def clear(self, render=True):
  self.contextView.GetScene().ClearItems()
  r, g, b = [c / 255. for c in self.canvas.backgroundcolor]
  self.contextView.GetRenderer().SetBackground(r, g, b)
+
+ if self.logoContextItem:
+ self.logoContextArea.ClearItems()
+ self.contextView.GetScene().RemoveItem(self.logoContextArea)
+ self.logoContextArea = None
+ self.logoContextItem = None
+ self.logoContextItemPython = None
+
  self._animationActorTransforms = {}
 
  self.showGUI(render=False)
@@ -1653,22 +1662,43 @@ def createLogo(self):
  position = [0.895, 0.0]
  position2 = [0.10, 0.05]
 
+ [renWinWidth, renWinHeight] = self.renWin.GetSize()
+ vpLowerLeftX = position[0] * renWinWidth
+ vpLowerLeftY = position[1] * renWinHeight
+ vpWidth = position2[0] * renWinWidth
+ vpHeight = position2[1] * renWinHeight
+
+ imgAspect = float(imgWidth) / imgHeight
+ vpAspect = vpWidth / vpHeight
+
+ if vpAspect > imgAspect:
+ # We'll use the full vp height and adjust it's width so that it's
+ # aspect ratio matches that of the image (so no stretching of the
+ # image occurs). The image should be centered, so we'll offset
+ # position x value by half the difference.
+ vpWidth = vpHeight * imgAspect
+ halfDiff = ((position2[0] * renWinWidth) - vpWidth) / 2.0
+ vpLowerLeftX += halfDiff
+ else:
+ # Similar to above, but in this case we choose to keep the vp width
+ # and adjust it's height.
+ vpHeight = vpWidth / imgAspect
+ halfDiff = ((position2[1] * renWinHeight) - vpHeight) / 2.0
+ vpLowerLeftY += halfDiff
+
  view = self.contextView
 
  area = vtk.vtkContextArea()
  view.GetScene().AddItem(area)
 
- [renWinWidth, renWinHeight] = self.renWin.GetSize()
  dataBounds = vtk.vtkRectd(0.0, 0.0, imgWidth, imgHeight)
- screenGeom = vtk.vtkRecti(
- int(position[0] * renWinWidth),
- int(position[1] * renWinHeight),
- int(position2[0] * renWinWidth),
- int(position2[1] * renWinHeight))
+ screenGeom = vtk.vtkRecti(int(vpLowerLeftX), int(vpLowerLeftY),
+ int(vpWidth), int(vpHeight))
 
  vcs2vtk.configureContextArea(area, dataBounds, screenGeom)
  area.GetDrawAreaItem().AddItem(item)
 
+ self.logoContextArea = area
  self.logoContextItem = item
  self.logoContextItemPython = pythonItem