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PNG count not transparent pixels
Posted: Sun Jan 01, 2017 1:32 am
by infratec
Hi,
I needed to compare the area of 2 estates.
Ok, I used google maps and grabbed the pictures.
I loaded the pictures in gimp and cut out the estates.
Then I saved each estate as png with transparence.
Now I needed only a tool to count the pixels.
After a short time of searching I used my 'swiss army knife' called PB
Code: Select all
UsePNGImageDecoder()
Filename$ = OpenFileRequester("Choose a file", "", "PNG|*.png", 0)
If Filename$ <> ""
If LoadImage(0, Filename$)
w = ImageWidth(0)
h = ImageHeight(0)
If StartDrawing(ImageOutput(0))
DrawingMode(#PB_2DDrawing_AllChannels)
For y = 0 To h - 1
For x = 0 To w - 1
P = Point(x, y)
If Alpha(P) <> 0
;Debug Str(x) + "x" + Str(y) + " " + Str(Alpha(P))
Count + 1
Plot(x, y, $FF0000FF)
EndIf
Next x
Next y
StopDrawing()
SaveImage(0, Filename$ + ".bmp", #PB_ImagePlugin_BMP)
MessageRequester("Info", "Found " + Str(Count) + " pixel")
EndIf
EndIf
EndIf
As test for the truth I store a bmp with all counted pixels in red.
In my case it worked.
Maybe someone can use it too.
Happy new year,
Bernd
Re: PNG count not transparent pixels
Posted: Sun Jan 01, 2017 12:59 pm
by Bisonte
/OT
infratec wrote:After a short time of searching I used my 'swiss army knife' called PB
I love this moments
OT/
Re: PNG count not transparent pixels
Posted: Sun Jan 01, 2017 5:37 pm
by infratec
An extended version:
Code: Select all
EnableExplicit
#Size = 380
Enumeration
#OrigPicture
#SmallOrigPicture
#SmallTestPicture
EndEnumeration
Define.i w, h, x, y, P, Count
Define.f FactorX, FactorY, Factor
Define Filename$
UsePNGImageDecoder()
Filename$ = OpenFileRequester("Choose a file", "", "PNG|*.png", 0)
If Filename$ <> ""
If LoadImage(#OrigPicture, Filename$)
w = ImageWidth(#OrigPicture)
h = ImageHeight(#OrigPicture)
CopyImage(#OrigPicture, #SmallOrigPicture)
FactorX = #Size / w
FactorY = #Size / h
If FactorX < FactorY
Factor = FactorX
Else
Factor = FactorY
EndIf
If Factor < 0
Factor = 1.0
EndIf
ResizeImage(#SmallOrigPicture, w * Factor, h * Factor)
OpenWindow(0, 0, 0, w * Factor * 2 + 30, h * Factor + 30 + 20, "PixelCount", #PB_Window_MinimizeGadget|#PB_Window_ScreenCentered)
ImageGadget(0, 10, 10, 0, 0, ImageID(#SmallOrigPicture), #PB_Image_Border)
ImageGadget(1, 10 + w * Factor + 10, 10, w * Factor, h * Factor, 0, #PB_Image_Border)
CreateStatusBar(0, WindowID(0))
AddStatusBarField(200)
If StartDrawing(ImageOutput(#OrigPicture))
DrawingMode(#PB_2DDrawing_AllChannels)
For y = 0 To h - 1
For x = 0 To w - 1
P = Point(x, y)
If Alpha(P) <> 0
;Debug Str(x) + "x" + Str(y) + " " + Str(Alpha(P))
Count + 1
Plot(x, y, $FF0000FF)
EndIf
Next x
Next y
StopDrawing()
CopyImage(#OrigPicture, #SmallTestPicture)
ResizeImage(#SmallTestPicture, w * Factor, h * Factor)
SetGadgetState(1, ImageID(#SmallTestPicture))
If Count = 0
StatusBarText(0, 0, "no transparent PNG", #PB_StatusBar_Center)
Else
StatusBarText(0, 0, "Found " + Str(Count) + " visible pixels", #PB_StatusBar_Center)
EndIf
EndIf
Repeat
Until WaitWindowEvent() = #PB_Event_CloseWindow
EndIf
EndIf
Bernd
Re: PNG count not transparent pixels
Posted: Sun Jan 01, 2017 11:26 pm
by netmaestro
Nice idea, kind of like dropping a blob of butter into a measuring cup that contains a predetermined amount of water. Butter raises the level, by how much tells you the volume of butter.
Switching to estates, if you know the greatest distance North to South and the greatest distance East to West covered by the estate, say it's 100m each way just for an example, the total would be 10,000 square meters. You could calculate the sqare meters of the estate like this:
number of visible px
----------------------- X 10,000
total number of px
which looks to me like a fair way to get the number of square meters covered by the estate.