In that case the patch is fine.
-phil.
On 03/20/2018 12:15 AM, Jayathirth D V wrote:
HI Phil,
Please find my observation:
In case of DIB header type BITMAPINFOHEADER/ BITMAPV4HEADER/
BITMAPV5HEADER, Microsoft
documentation(https://msdn.microsoft.com/en-us/library/dd183376(v=vs.85).aspx
<https://msdn.microsoft.com/en-us/library/dd183376%28v=vs.85%29.aspx>
) mentions that mask values are valid only when compression type is
BI_BITFIELDS. When compression type is BI_RGB which ii no compression,
Microsoft document mentions that
1)For 16 bpp : “The relative intensities of red, green, and blue are
represented with five bits for each color component. The value for
blue is in the least significant five bits, followed by five bits each
for green and red. The most significant bit is not used.”. So
basically it should be RGB555.
2)For 32 bpp : “Each DWORD in the bitmap array represents the relative
intensities of blue, green, and red for a pixel. The value for blue is
in the least significant 8 bits, followed by 8 bits each for green and
red. The high byte in each DWORD is not used”. So basically it should
be XRGB8888.
This is why we have redMask = 0x7C00, greenMask = 0x3E0, blueMask =
0x1F in case of 16bpp and redMask = 0x00FF0000, greenMask =
0x0000FF00, blueMask = 0x000000FFfor 32bpp for all the three standard
formats BITMAPINFOHEADER, BITMAPV4HEADER and BITMAPV5HEADER.
Since BITMAPV2INFOHEADER & BITMAPV3INFOHEADER support falls in between
that of other Microsoft documented DIB header types it is good that we
follow the same approach in case of BITMAPV2INFOHEADER &
BITMAPV3INFOHEADER also.
Please let us know your inputs.
Thanks,
Jay
*From:*Phil Race
*Sent:* Monday, March 19, 2018 11:07 PM
*To:* Jayathirth D V; 2d-dev
*Subject:* Re: [OpenJDK 2D-Dev] [11] RFR JDK-7031957: DIB header of
type BITMAPV2INFOHEADER & BITMAPV3INFOHEADER is not supported in
BMPImageReader
Since the principal addition of these formats is to add explicit fields
for supporting the bitmasks for accessing R/G/B/A it seems odd to
see there is code like this which ignores it when the data is uncompressed
by using these hardcoded values :
456 if ((int)compression == BI_RGB) {
457 redMask = 0x7C00;
458 greenMask = 0x3E0;
459 blueMask = 0x1F;
I do see that it seems likely you copied this from the 108/124 case
but I'd like to see some proof that this is correct.
-phil.
On 03/14/2018 03:39 AM, Jayathirth D V wrote:
Hello All,
Please review the following solution in JDK11 :
Bug : https://bugs.openjdk.java.net/browse/JDK-7031957
Webrev : http://cr.openjdk.java.net/~jdv/7031957/webrev.00/
<http://cr.openjdk.java.net/%7Ejdv/7031957/webrev.00/>
_Issue:_ If we try to read any BMP image of DIB header type
BITMAPV2INFOHEADER/ BITMAPV3INFOHEADER, we get IOException
mentioning the BMP image type in not yet implemented.
_Root cause: _ BMPImageReader doesn’t support DIB header types
BITMAPV2INFOHEADER/ BITMAPV3INFOHEADER we support only
BITMAPCOREHEADER, BITMAPINFOHEADER, BITMAPV4HEADER & BITMAPV5HEADER.
_Solution:_ Many other tools like GIMP, Microsoft PowerPoint,
IrfanView support BITMAPV2INFOHEADER & BITMAPV3INFOHEADER format
BMP images. We can consider BITMAPV2INFOHEADER &
BITMAPV3INFOHEADER header types having functionality in between
that of BITMAPINFOHEADER & BITMAPV4HEADER. BITMAPINFOHEADER with
type BITFIELDS & extra 4 bytes for alpha channel or First 56 bytes
of BITMAPV4HEADER is nothing but BITMAPV3INFOHEADER.
To support BITMAPV2INFOHEADER & BITMAPV3INFOHEADER we can use
similar approach of what we are doing while decoding first 56
bytes under BITMAPV4HEADER. So I have added additional “if()” to
do the same, we can merge decoding of BITMAPV2INFOHEADER &
BITMAPV3INFOHEADER at the same place where we are decoding
BITMAPV4HEADER but we need to add many branch conditions to follow
that approach.
Thanks,
Jay
