Hello,


I am using a library which returns a byte[] containing RAW data, ie all
pixels' color values coded in a byte array without header. I would like to
save those data into a JPEG file so I tried to use the MetaFile class.

byte[] data;
(...) // Creating the RAW image through the DLL call.
MemoryStream memoryStream = new MemoryStream(data);
MetaFile metaFile = new MetaFile(memoryStream);

Unfortunately, this code throws an exception which description is: "GDI+
encounters an internal error". I also tried this:

byte[] data;
(...) // Creating the RAW image through the DLL call.
MemoryStream memoryStream = new MemoryStream(data);
Image image = Image.FromStream(memoryStream);

This time I have an ArgumentException. I guess I can't use a stream
linking to RAW data as it is not an image with header. But then, how can I
make the MetaFile class read my data and convert them to JPEG file ???

Thank you !


Laurent

If you wish to save your raw data as a .jpeg file, you need to create a
bitmap from the raw bytes and then have the gdiplus encoder create a .jpeg
file for you.

1) Using your memory stream, create and populate in order:
BITMAPFILEHEADER
BITMAPINFOHEADER
palette(i.e., if raw data is indexed)
RAW bytes
2) You now have a correctly formatted bitmap that the gdiplus decoder will
create a bitmap from your memory stream.
3) Use the save method to save your bitmap as a .jpeg encoded file.


"Laurent Navarro" <(E-Mail Removed)> wrote in message
news:eH%(E-Mail Removed)...
> Hello,
>
>
> I am using a library which returns a byte[] containing RAW data, ie all
> pixels' color values coded in a byte array without header. I would like to
> save those data into a JPEG file so I tried to use the MetaFile class.
>
> byte[] data;
> (...) // Creating the RAW image through the DLL call.
> MemoryStream memoryStream = new MemoryStream(data);
> MetaFile metaFile = new MetaFile(memoryStream);
>
> Unfortunately, this code throws an exception which description is:
> "GDI+ encounters an internal error". I also tried this:
>
> byte[] data;
> (...) // Creating the RAW image through the DLL call.
> MemoryStream memoryStream = new MemoryStream(data);
> Image image = Image.FromStream(memoryStream);
>
> This time I have an ArgumentException. I guess I can't use a stream
> linking to RAW data as it is not an image with header. But then, how can I
> make the MetaFile class read my data and convert them to JPEG file ???
>
> Thank you !
>
>
> Laurent
>

Hi Michel,


Thank you for your answer. I tried and it worked, but I had a bad
surprise: the GDI+ works in BGR and not RGB. So before saving my datas I had
to swap the R and B value for each pixel of my data.

Is there an easier way to make the Bitmap class work in RGB without
converting the image first ?

Thanks



"Michael Phillips, Jr." <(E-Mail Removed)0m> a écrit dans le
message de news: eI3%(E-Mail Removed)...
> If you wish to save your raw data as a .jpeg file, you need to create a
> bitmap from the raw bytes and then have the gdiplus encoder create a .jpeg
> file for you.
>
> 1) Using your memory stream, create and populate in order:
> BITMAPFILEHEADER
> BITMAPINFOHEADER
> palette(i.e., if raw data is indexed)
> RAW bytes
> 2) You now have a correctly formatted bitmap that the gdiplus decoder will
> create a bitmap from your memory stream.
> 3) Use the save method to save your bitmap as a .jpeg encoded file.
>
>
> "Laurent Navarro" <(E-Mail Removed)> wrote in message
> news:eH%(E-Mail Removed)...
>> Hello,
>>
>>
>> I am using a library which returns a byte[] containing RAW data, ie
>> all pixels' color values coded in a byte array without header. I would
>> like to save those data into a JPEG file so I tried to use the MetaFile
>> class.
>>
>> byte[] data;
>> (...) // Creating the RAW image through the DLL call.
>> MemoryStream memoryStream = new MemoryStream(data);
>> MetaFile metaFile = new MetaFile(memoryStream);
>>
>> Unfortunately, this code throws an exception which description is:
>> "GDI+ encounters an internal error". I also tried this:
>>
>> byte[] data;
>> (...) // Creating the RAW image through the DLL call.
>> MemoryStream memoryStream = new MemoryStream(data);
>> Image image = Image.FromStream(memoryStream);
>>
>> This time I have an ArgumentException. I guess I can't use a stream
>> linking to RAW data as it is not an image with header. But then, how can
>> I make the MetaFile class read my data and convert them to JPEG file ???
>>
>> Thank you !
>>
>>
>> Laurent
>>
>
>