One day, I had this weird idea of displaying an animation in Excel using the cells as pixels.
First of all, I had to check if it was possible at all, and also how fast Excel would render the "pixels".
So I grabbed a 320x200 image of Dangerous Dave here and set off...
To convert a PNG file to CSV I used this PHP tool.
VBA code:
'Canvas reset button
Sub Button2_Click()
Range("A1:LH200").ColumnWidth = 0.25
Range("A1:LH200").RowHeight = 2
Range("A1:LH200").Interior.ColorIndex = 0
End Sub
'Draw button
Sub Button1_Click()
DrawCSVFile
End Sub
`The draw subroutine itself
Public Sub DrawCSVFile()
Dim FilePath As String
FilePath = ActiveWorkbook.Path & "\title1.csv"
Open FilePath For Input As #1
Y = 1
Do Until EOF(1)
Line Input #1, LineFromFile
LineItems = Split(LineFromFile, ",")
For X = 1 To 320
RGBString = LineItems(X - 1)
R = Val("&H" & Mid(RGBString, 1, 2))
G = Val("&H" & Mid(RGBString, 3, 2))
B = Val("&H" & Mid(RGBString, 5, 2))
RGBExcel = RGB(R, G, B)
Cells(Y, X).Interior.Color = RGBExcel
Next
Y = Y + 1
Loop
Close #1
End Sub
The result: well, it works :)
But the image above took a full whopping minute to draw.
Reading the CSV line by line and painting individual pixels turned out to be really slow!
I guess some day I should try the range copy method :)
A couple of things I learned along the way:
- while reading a text file, VBA expects the lines to end with CR or CRLF (in Windows at least); LF is not recognized as the line end
- RGB in Excel is actually BGR
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