Create a Bitmap from an Array

[Lance]

I need to create a Drawing.Bitmap from an array of integer
values. My current technique creates a bitmap that
eventually becomes corrupt (i.e., the bitmap's pixels
change to a different color after a while). Can somebody
please tell me what I'm doing wrong? Here is a sample:

Public Shared Function CreateBitmapFromArray( _
ByVal width As Integer, _
ByVal height As Integer, _
ByVal pixelFormat As Drawing.Imaging.PixelFormat, _
ByVal pixelValues() As Integer) As Drawing.Bitmap

'Get a pinned handle of pixelValues.
Dim pixelValuesHandle As
System.Runtime.InteropServices.GCHandle = _
System.Runtime.InteropServices.GCHandle.Alloc
(pixelValues, Runtime.InteropServices.GCHandleType.Pinned)

'Get a pointer to the pixelValues that is used to
create the bitmap.
Dim scan0 As System.IntPtr =
pixelValuesHandle.AddrOfPinnedObject

'Get the stride of the resulting bitmap.
Dim stride As Integer = GetStride(width, pixelFormat)

'Create a bitmap from pixelValues.
Dim bitmap As New Drawing.Bitmap(width, height,
stride, pixelFormat, scan0) 'Return value.

'Release the handle.
pixelValuesHandle.Free()

Return bitmap
End Function

Thanks,
Lance

 

[Ken Tucker [MVP]]

Hi,

Not sure if this will help. This is how you create an bitmap from
an byte array.

Dim bm As Bitmap

Dim arByte() As Byte = objData ' Your data

Dim ms As New System.IO.MemoryStream

ms.Write(arByte, 0, arByte.Length)

bm = New Bitmap(ms)

Ken

 

[Lance]

Thanks, but what I really need to know is how to create a
bitmap from an array of integer values using the
following Bitmap constructor:

Public Sub New( _
ByVal width As Integer, _
ByVal height As Integer, _
ByVal stride As Integer, _
ByVal format As PixelFormat, _
ByVal scan0 As IntPtr _
)

Lance

 

[Herfried K. Wagner [MVP]]

Not sure if this will help. This is how you create an bitmap from
an byte array.

Dim bm As Bitmap

Dim arByte() As Byte = objData ' Your data

Dim ms As New System.IO.MemoryStream

ms.Write(arByte, 0, arByte.Length)

bm = New Bitmap(ms)

Notice that this will require the whole bitmap file to be stored inside
the byte array.

 

[Bob Powell [MVP]]

This constructor referrs to the data that would be found in a BitmapData
object after a lockbits method had been called.

The GDI+ FAQ has an article on LockBits and explains the data structure in
the BitmapData object. Perhaps that will help y0u out.

--
Bob Powell

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[Cor]

Hi Lance,

This would do it I think, but you have to check it firm, because it is
pasted from everywhere (I have it in all kind of functions) so see it as a
roughly made example (nothing with stride because I do not use that)
\\
Dim originalImage As Image
Dim ms As New MemoryStream(arrPicture)
originalImage = Image.FromStream(ms)
Dim originalRect
Dim pictureRect As Rectangle
'set the rectangle properties
bmpCropped = New Bitmap(picturerect.Width, picturerect.Height)
Dim grBitmap As Graphics = Graphics.FromImage(bmpCropped)
grBitmap.DrawImage(originalImage, pictureRect, originalRec,
GraphicsUnit.Pixel)
picToShow.Image = bmpCropped
//

I hope this helps,

Cor


"> Thanks, but what I really need to know is how to create a

 

[Lance]

-----Original Message-----

This constructor referrs to the data that would be found in a BitmapData
object after a lockbits method had been called.

Yep, that tells me what I needed to know. Lockbits it is
then. Thanks!