Drawing a grid over an image
PRobbins
grid over it that the user can toggle on and off. Currently, when the
user tells the program to skip to the next image I set a static bitmap
to a wxBitMapFromImage. I've been doing some research and I think I
may need to use a DC to draw a grid on the image before I turn it into
a bitmap, but this could be completely off base. This is the first
time I have worked with images in wxPython and I'm having trouble
figuring this out. Thanks in advance.
Benjamin Herwig
blitting...". My question seems to be similar to your's!
Mike Driscoll
Once you know how to do that, I would just grab the image's size and draw the grid programmatically. There are some text overlay examples in one of the examples on this page: http://wiki.wxpython.org/WorkingWithImages
- Mike
Robin Dunn
There are a number of approaches that could be used, and which is best
depends on the needs of your application. You could draw it all
yourself without using a separate wx.StaticBitmap, for example in a
paint event for the parent window draw the bitmap and then draw the
grid. Or you could create a new bitmap from the original image plus the
grid, using a wx.MemoryDC, and then either draw the new bitmap, or use
it in a wx.StaticBitmap, etc.
You should take a look at the ScrolledWindow sample in the demo (or
several others in the demo or the wiki) for an example of drawing things
on windows.
--
Robin Dunn
Software Craftsman
http://wxPython.org
PRobbins
exactly is Paint event actually called? In my application the image
shows up on the screen unchanged at first. The user can choose a
radio button for a 3x3, 6x6, 9x9 grid or no grid at all. I need the
grid to show up as soon as the radio button is selected. Will a paint
event be called? If not, can I manually call a paint event?
On Apr 12, 4:08 pm, Ray Pasco <pascor22...@gmail.com> wrote:
> <https://lh3.googleusercontent.com/_2DvUrnDWjI4/TaSw5KQKMvI/AAAAAAAAAC...>
> very little algebra.
>
> Ray Pasco
>
> 3KViewDownload
>
> GuidoInTheComfyChair.PNG
> 358KViewDownload
Cody Precord
On Wed, Apr 13, 2011 at 9:11 AM, PRobbins <pjrob...@gmail.com> wrote:
> Thanks for the help. One point I'm a little confused on...when
> exactly is Paint event actually called? In my application the image
> shows up on the screen unchanged at first. The user can choose a
> radio button for a 3x3, 6x6, 9x9 grid or no grid at all. I need the
> grid to show up as soon as the radio button is selected. Will a paint
> event be called? If not, can I manually call a paint event?
>
Yes, simply call Refresh() on the window that is bound to the paint event.
Cody
PRobbins
sticking out from behind the image now and whenever the image
refreshes I can briefly see the grid flash on the screen before it is
covered up by the image. Any idea what's going on? How can I make my
image transparent and/or put the grid on top? Sorry if some of these
questions are elementary, this is really the first time I've worked
with images in wxPython before.
On Apr 12, 4:08 pm, Ray Pasco <pascor22...@gmail.com> wrote:
> <https://lh3.googleusercontent.com/_2DvUrnDWjI4/TaSw5KQKMvI/AAAAAAAAAC...>
> very little algebra.
>
> Ray Pasco
>
> 3KViewDownload
>
> GuidoInTheComfyChair.PNG
> 358KViewDownload
Cody Precord
On Wed, Apr 13, 2011 at 9:50 AM, PRobbins <pjrob...@gmail.com> wrote:
> Ok I have implemented your suggestions and I can see bits of the grid
> sticking out from behind the image now and whenever the image
> refreshes I can briefly see the grid flash on the screen before it is
> covered up by the image. Any idea what's going on? How can I make my
> image transparent and/or put the grid on top? Sorry if some of these
> questions are elementary, this is really the first time I've worked
> with images in wxPython before.
>
Can't say without knowing what your doing.
Please make a runnable, small as possible sample
(http://wiki.wxpython.org/MakingSampleApps) that demonstrates the
problem.
I also attached a simple example that you can try out.
Regards,
Cody
https://www.packtpub.com/wxpython-2-8-application-development-cookbook/book
PRobbins
enough sample. Here is the relevant code from my program however:
First I am creating a panel and putting a Static Bitmap on it:
self.browserPanel = wx.Panel(self)
self.fgs=wx.FlexGridSizer(cols=1, hgap=1, vgap=1)
#Creat a Static bitmap with a dummy image
self.ibrowserBitmap = wx.StaticBitmap(self, -1,
wx.EmptyBitmap(50,50))
self.fgs.Add(self.ibrowserBitmap)
self.Bind(wx.EVT_PAINT, self.OnPaint)
self.loadCurrentImage()
Second, here is the function loadCurrentImage():
def loadCurrentImage(self):
'''
Loads the current image based off Workspace.currentImageIndex.
This function is called after every image change.
'''
try:
self.currentImage = Workspace.data.getImageDirectory() +
os.sep + Workspace.data.getImageName(Workspace.currentImageIndex)
except:
Workspace.currentImageIndex = 1
self.img = simple_image.Image()
if enhanceTool.norm.GetValue()==True:
self.img.normalize('RGB')
if enhanceTool.norm.GetValue()==False:
self.img.normalize(None)
if enhanceTool.eq.GetValue()==True:
self.img.equalize('RGB')
if enhanceTool.eq.GetValue()==False:
self.img.equalize(None)
if enhanceTool.sharp.GetValue()==True:
self.img.enhanceSharpness(2.0)
if enhanceTool.sharp.GetValue()==False:
self.img.enhanceSharpness(1.0)
if enhanceTool.invert.GetValue()==True:
self.img.invert(True)
if enhanceTool.invert.GetValue()==False:
self.img.invert(False)
self.img.load(self.currentImage)
imageBrowser.iWidth = self.img.wx().GetWidth()
imageBrowser.iHeight = self.img.wx().GetHeight()
self.img =
self.img.wx().Scale(imageBrowser.iWidth*Workspace.zoomScale,
imageBrowser.iHeight*Workspace.zoomScale)
self.ibrowserBitmap.SetBitmap(wx.BitmapFromImage(self.img))
self.bmpWidth, self.bmpHeight = self.ibrowserBitmap.GetSize()
self.Refresh()
self.Fit()
Finally, here is my OnPaint function:
def OnPaint(self, event):
paintDC = wx.PaintDC(self.browserPanel)
if self.GRIDSIZE != 0:
paintDC.SetBackgroundMode(wx.TRANSPARENT)
numRows, numCols = self.GRIDSIZE, self.GRIDSIZE
gridWid, gridHgt = paintDC.GetSizeTuple()
cellWid = float( gridWid - 1) / numRows
cellHgt = float( gridHgt - 1) / numCols
paintDC.SetBrush( wx.Brush( wx.BLACK, wx.TRANSPARENT) )
paintDC.SetPen( wx.Pen( wx.BLACK, 1, wx.SOLID) )
paintDC.DrawRectangle( 0, 0, gridWid, gridHgt )
for rowNum in xrange( numRows + 1) :
paintDC.DrawLine( 0, rowNum*cellHgt, gridWid,
rowNum*cellHgt )
for colNum in xrange( numCols + 1 ) :
paintDC.DrawLine( colNum*cellWid, 0, colNum*cellWid,
gridHgt )
event.Skip()
>
> paint.py
> 3KViewDownload
Cody Precord
On Wed, Apr 13, 2011 at 10:39 AM, PRobbins <pjrob...@gmail.com> wrote:
> My application is quite large so I'm not sure I can make a small
> enough sample. Here is the relevant code from my program however:
>
> First I am creating a panel and putting a Static Bitmap on it:
Thats your problem then. The StaticBitmap is a separate window from
the one your drawing on. So your drawing on its parent and then the
StaticBitmap is getting displayed over it.
Draw the bitmap in the OnPaint handler instead of using a StaticBitmap
control. See the sample I attached to the previous message and replace
the DrawCircle code with DrawBitmap to draw your Bitmap instead.
Cody
PRobbins
steps with understanding how this works though. In my above code, I
create the static bitmap and then every time the user asks the program
to switch images, the bitmap is set to a new bitmap created from the
image self.img. If I'm understanding you correctly, you want me to
draw the new images bitmap in the OnPaint function, then draw the grid
lines over it, right?
Cody Precord
On Wed, Apr 13, 2011 at 11:19 AM, PRobbins <pjrob...@gmail.com> wrote:
> Ok, I think I understand where you're going. I'm still taking baby
> steps with understanding how this works though. In my above code, I
> create the static bitmap and then every time the user asks the program
> to switch images, the bitmap is set to a new bitmap created from the
> image self.img. If I'm understanding you correctly, you want me to
> draw the new images bitmap in the OnPaint function, then draw the grid
> lines over it, right?
>
Yes, I think you will find that to work much better for this type of task.
Cody
p.s) this group prefers bottom posting when replying to messages.
(http://www.caliburn.nl/topposting.html)
PRobbins
any worthwhile progress. I'm coming in and working on code that
someone else has written so my hands are tied a little bit as far as
restructuring it. I've poked around the forums and wxPython website/
code samples a bit more and I was wondering if I could solve my
problem by keeping the static bitmap and converting my image to a
bitmap, using a memory DC, drawing the gridlines on it and loading the
resulting bitmap into the static bitmap?
Ray Pasco
Ray
Cody Precord
On Wed, Apr 13, 2011 at 1:04 PM, PRobbins <pjrob...@gmail.com> wrote:
>
>
> I've played around with this suggestion a little bit and haven't made
> any worthwhile progress. I'm coming in and working on code that
> someone else has written so my hands are tied a little bit as far as
> restructuring it. I've poked around the forums and wxPython website/
> code samples a bit more and I was wondering if I could solve my
> problem by keeping the static bitmap and converting my image to a
> bitmap, using a memory DC, drawing the gridlines on it and loading the
> resulting bitmap into the static bitmap?
>
It adds some extra steps, but you can certainly do that too.
You would need to get rid of the OnPaint handling and add an method
that you would have to manually call when you change the grid layout
or image that is being displayed to update the StaticBitmap control
with a new Bitmap.
Pretty much been handed the code to do what you need to do already so
not sure what else you are stuck on at this point. Highly suggest
making a minimal sample app as mentioned before, as you there is a
good chance you would figure out what your doing wrong while writing
the sample.
Cody
Ray Pasco
Have you looked at either of the code examples ? Both draw grid lines over top a wx.Bitmap in the same way. They both work with a wx.Bitmap, not a wx.StaticBitmap. When a wx.PaintDC is created it's wx.Bitmap is the bitmap of the interior (Client) of whatever window is the parameter to the PaintDC. Cody's example uses the implicit bitmap from a wx.Panel while mine uses a wx.Bitmap created from a graphic (photo) file.
Ray
PRobbins
> You had best not use a wx.StaticBitmap at all. All you need is a wx.Bitmap
> to do everything you want to do.The bitmap can be created directly from a
> graphic file.
>
> Have you looked at either of the code examples ? Both draw grid lines over
> wx.StaticBitmap*. When a wx.PaintDC is created it's wx.Bitmap is the bitmap
> Cody's example uses the implicit bitmap from a wx.Panel while mine uses a
> wx.Bitmap created from a graphic (photo) file.
>
> Ray