John Labenski <[email protected]> wrote:
(11/05/2009 01:16)
>A few comments about your code. You should call wxFrame::Show(true) as the
>last line in your window creation code to allow it to be laid out properly.
Ok, I'd chosen to do it earlier to avoid flow conflicts so I could show some
info in a frame while the bitmap loaded and data got processed, but I've
learned enough about changing pre-created stuff to show it and change it later,
so the new code (complete rewrite, as explained below) does this now.
>You should use the wxMouseEvent's position function.
>
True. In some of my tests I do, that one had some older code lines. I had to
correct this same thing a few hours ago in the new scheme I've worked up.
>You select a wxBitmap into the wxMemoryDC before using it right? wxBitmaps
>may not be initialized on creation so it's full of random bits, but I am not
>sure of this. You can always draw a rectangle to clear it.
Yes, I did that to test it but what's interesting is what happens when you
don't. :) Specifically what's really cool is what happens when two panels are
used, same size, same parent. That was my initial, original attempt, and I saw
this strange behaviour that I decided to exploit. The Layer (overlay) panel is
created FIRST, but 'appears' on top, I connect all user-control events to the
layer, not the visible panel. In OnPaint() I draw the bitmap to the Chart panel
then draw stuff on the Layer panel so it appears to draw on the image directly,
but does not, as the right mouse click will demonstrate in the new code.
Regarding the other mails about the Rat-racing Mousewheel, I tried
event:Skip(false) but that also failed to stop it, but I'd already written
something new, bypassing the issue entirely, as you say, I needed to avoid
conflict with existing behaviour, so I went for a basic direct method. I'll
describe how, and first why:
If I do DrawBitmap(BITMAP,0,0,false) with the DC being a panel that was
scrolled to 20,20, I'd expect to see the bitmap offset by 20 pixels in each
axis along with the panel. This I did not see. I found that the 0,0 in
DrawBitmap() overrode it, so I decided to forget the ScrolledWindow() AND the
general Panel:ScrollWindow() method. I decided to modify the DrawBitmap axis
values directly and base all my calculations around that. Not only does it
work, but it performs better by far than the original ScrolledWindow did, no
fighting with inbuilt behaviour, and it's faster, and does not have the
horrible dual-tracked flicker that moving the ScrolledWindow did when grabbing
it and scrolling both axes at once. it works as clean and fast as in any
program I've seen on this system now.
function Main()
FRAME=wx.wxFrame(wx.NULL,-1,"",wx.wxDefaultPosition,wx.wxSize(800,600),wx.wxDEFAULT_FRAME_STYLE)
FRAME:CreateStatusBar() FRAME:SetStatusText(" ")
LAYER=wx.wxPanel(FRAME,-1,wx.wxPoint(0,0))
PANEL=wx.wxPanel(FRAME,-1,wx.wxPoint(0,0))
TT=wx.wxToolTip(" \n") LAYER:SetToolTip(TT)
FRAME:Centre() FRAME:Show(true)
BITMAP=wx.wxBitmap("Something big, maybe 9000,6000 pixels.jpg")
BX,BY,LX,LY,OX,OY,MX,MY=BITMAP:GetWidth(),BITMAP:GetHeight(),0,0,0,0,0,0
TOGGLE=1
FRAME:Connect(wx.wxEVT_SIZE,ReSize)
LAYER:Connect(wx.wxEVT_RIGHT_DOWN,function(E) TOGGLE=1-TOGGLE
PANEL:Refresh() LAYER:Refresh() end)
LAYER:Connect(wx.wxEVT_MOTION,OnMotion)
LAYER:Connect(wx.wxEVT_ERASE_BACKGROUND,function() end)
PANEL:Connect(wx.wxEVT_ERASE_BACKGROUND,function() end)
LAYER:Connect(wx.wxEVT_PAINT,OnPaint)
collectgarbage("collect")
end
TABLE={{}} TABLE[0]={}
for X=0,1270,20 do table.insert(TABLE[1],X) table.insert(TABLE[1],0)
table.insert(TABLE[1],X) table.insert(TABLE[1],1023) end
for Y=0,1014,20 do table.insert(TABLE[0],0) table.insert(TABLE[0],Y)
table.insert(TABLE[0],1279) table.insert(TABLE[0],Y) end
function ReSize(E)
CX,CY=FRAME:GetClientSizeWH() PANEL:SetClientSize(CX,CY)
LAYER:SetClientSize(CX,CY) CX,CY=CX-BX,CY-BY
if LX<(CX) then LX=CX end if LY<(CY) then LY=CY end LAYER:Refresh()
PANEL:Refresh()
end
--==================== Mouse Handling ====================--
function OnMotion(E)
if E:LeftIsDown() then
LX,LY=OX+E:GetX()-MX,OY+E:GetY()-MY TT:SetTip("")
if LX>0 then LX=0 end if LY>0 then LY=0 end if LX<(CX) then LX=CX
end if LY<(CY) then LY=CY end
PANEL:Refresh() LAYER:Refresh()
else OX,OY=LX,LY MX,MY=E:GetX(),E:GetY()
TT:SetTip("X = "..E:GetX()-OX.."\nY = "..E:GetY()-OY)
end
end
--==================== Track Drawing =====================--
function OnPaint(E)
local DC=wx.wxPaintDC(PANEL)
if BITMAP then DC:DrawBitmap(BITMAP,LX,LY,false) end
DC:delete()
local DC,P=wx.wxPaintDC(LAYER),wx.wxPen() P:SetColour(255,0,0) P:SetWidth(1)
DC:SetPen(P)
for N=1,#TABLE[TOGGLE]-2,2 do
DC:DrawLine(TABLE[TOGGLE][N]+LX,TABLE[TOGGLE][N+1]+LY,TABLE[TOGGLE][N+2]+LX,TABLE[TOGGLE][N+3]+LY)
end
DC:delete() P:delete()
end
Main()
I invite you to try to break it. :) So far as I can tell it's resistant to any
kind of strange stuff like starting a drag from the status bar onto the client
area, a trick which even Scribble will balk at, I found, at least, it will if
it's done before the first line is drawn. Another thing I found is that the
current method allows a lot of reduction, it's the simplest as well as the best
form I've done to date, withu no strange responses to user input if it's
resized or if the drag movement goes beyond the edge and stops, or returns.
So long as that dual-panel transparency trick doesn't invoke something it
shouldn't, I'm going to stay with it, though I do have a fallback plan of
grabbing a client-area-sized peice of the bitmap as overlay to draw on if I
must. That would be slower though.
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