ARGBData Property

Retrieves the raw image bits as a Vector of Long values.

Syntax

[ ppResult = ] ImageFile.ARGBData

Possible Values

ppResult

Vector value of image bits.

The property is read-only. The property has no default value.

Remarks

The ARGBData property returns a Vector of Long values that contain raw ARGB bitmap data. Each Long value represents a pixel. The first value corresponds to the pixel at the upper left and proceeds to the right, then down. When organized this way, the count of Long values in the Vector will be the product of the image's width and height.

You can use the following function to calculate the index of a specific pixel by its (x,y) coordinate and return the value of the Vector at that location.

Function GetPixel(v, x, y, width, height) 
    If x > width Or x < 1 Or _ 
        y > height Or y < 1 Or _ 
        v.Count <> width * height Then 
        GetPixel = 0 
        Exit Function 
    End If 
    
    GetPixel = v(x + (y - 1) * width) 
End Function 

Each Long value contains 4 bytes, the first byte (or high-order byte) represents the Alpha value. An Alpha value of 255 is completely opaque. An Alpha value of 0 is completely transparent (for Image types that support tranparency). Each subsequent byte corresponds to the Red, Green, and Blue value respectively.

The following example includes functions that show how to acquire the individual Alpha, Red, Green, and Blue values from a Long ARGB value.

Function Get4ByteHex(val)
    Dim s As String
    s = Hex(val)
    Do While Len(s) < 8
        s = "0" & s
    Loop
    Get4ByteHex = Right(s, 8)
End Function

Function Get1ByteHex(val)
    Dim s As String
    s = Hex(val)
    Do While Len(s) < 2
        s = "0" & s
    Loop
    Get1ByteHex = Right(s, 2)
End Function

Function GetAlpha(val)
    Dim s As String
    s = Get4ByteHex(val)
    GetAlpha = CLng("&h" & Left(s, 2))
End Function

Function GetRed(val)
    Dim s As String
    s = Get4ByteHex(val)
    GetRed = CLng("&h" & Mid(s, 3, 2))
End Function

Function GetGreen(val)
    Dim s As String
    s = Get4ByteHex(val)
    GetGreen = CLng("&h" & Mid(s, 5, 2))
End Function

Function GetBlue(val)
    Dim s As String
    s = Get4ByteHex(val)
    GetBlue = CLng("&h" & Right(s, 2))
End Function

Function GetARGB(a, r, g, b)
    Dim s As String
    s = "&h" & Get1ByteHex(a) & Get1ByteHex(r) & Get1ByteHex(g) & Get1ByteHex(b)
    GetARGB = CLng(s)
End Function

For additional example code, see ARGB Filter: Create a Modified Version of an Image.

Property Information

Minimum operating systems

Windows XP SP1

See Also

ImageFile, FileData, SubTypeValues, Vector