Hi Jim,
Gentle reminder. Please let me your inputs after testing.
Thanks,
Jay
-----Original Message-----
From: Jayathirth D V
Sent: Tuesday, February 16, 2016 10:03 PM
To: Jim Graham
Cc: 2d-dev@openjdk.java.net; Philip Race; Prasanta Sadhukhan
Subject: RE: [OpenJDK 2D-Dev] Review Request for JDK-7116979 : Unexpected pixel
colour when converting images to TYPE_BYTE_INDEXED
Hi Jim,
Thanks for letting me know about the importance of custom color maps. I was not
able to understand what you mentioned previously since I am new to this
terminology.
Regarding performance I checked with image having complete 255,255,128 pixels
and ran it for 100 times. I am running on Windows 7 Professional SP1 with
Intel i5-5300U CPU. Overall I don't see much difference in time taken for
drawImage() API before and after change. Details for INT_RGB image as input:
Before change :
Minimum time 536827ns
Maximum time 1560947ns
Average time 871167ns
After change :
Minimum time 536380ns
Maximum time 1468130ns
Average time 830778ns
There is +/- 10% delta both for before and after change time but there is no
major gap. Even for image with other input type it holds the same.
Regarding custom color maps, previously I ran on default color map generated in
TYPE_BYTE_INDEXED constructor. Now I tested with modified color map so that it
doesn't contain any of the primary color values. Instead of using 0-255 values
with value 51 increments in R,G,B components I used color map with 20-245
values with value 45 as increment. For this color map before and after change
all the pixels are referring to same index in color map irrespective of removal
of error delta addition in case of primary colors.
I have attached log for Red and Green primary colors before and after
change(Was not able to attach for more since it exceeded 120KB mailing list
limit). Please search for "Final index value =" in the logs. Please let me know
your inputs.
Thanks,
Jay
-----Original Message-----
From: Jim Graham
Sent: Tuesday, February 16, 2016 1:03 AM
To: Jayathirth D V
Cc: 2d-dev@openjdk.java.net; Philip Race; Prasanta Sadhukhan
Subject: Re: [OpenJDK 2D-Dev] Review Request for JDK-7116979 : Unexpected pixel
colour when converting images to TYPE_BYTE_INDEXED
Hi Jayathirth,
The issue with testing performance with white images is that the tests allow
the code to eliminate 3 indexed fetches which take time. Primary colors end up
being the one obscure case where the new code might be faster. But,
non-primary colors would be slower by a fair amount, so performance testing
with converting a randomized or non-primary-color image are the more telling
case. An image filled with 255,255,128 would be the worst case because it
would involve all of the tests and still have to do all of the lookups.
My question about how this works with custom colormaps was not really addressed
by your response. A simple test to make sure the colormap has accurate (or
very close) conversions for the primary colors may be enough to validate the
colormap for the indicated tests. If the colormap contains no pure conversions
for some of the primary colors then they may need to be dithered anyway...
...jim
On 2/15/16 3:39 AM, Jayathirth D V wrote:
> Hi Jim,
>
> I performed performance analysis with white image so that all
> conditions are checked in the new branch added. There is no major
> difference in time taken before and after change. For each input I
> have tested time taken for drawImage() API to convert from every
> format to Byte indexed type. For every unique conversion test is run
> for 100 times. Please find the details:
>
> Input
>
> type
>
>
>
> Min
>
> before change
>
> (ns)
>
>
>
> Min
>
> after change
>
> (ns)
>
>
>
> Max
>
> before change
>
> (ns)
>
>
>
> Max
>
> after change
>
> (ns)
>
>
>
> Average
>
> before change
>
> (ns)
>
>
>
> Average
>
> after
>
> change
>
> (ns)
>
> INT_RGB
>
>
>
> 523437
>
>
>
> 481491
>
>
>
> 1230724
>
>
>
> 1270440
>
>
>
> 789452
>
>
>
> 666144
>
> INT_ARGB
>
>
>
> 500232
>
>
>
> 493986
>
>
>
> 12406307
>
>
>
> 1308816
>
>
>
> 793384
>
>
>
> 654015
>
> INT_ARGB_PRE
>
>
>
> 500233
>
>
>
> 492201
>
>
>
> 1037057
>
>
>
> 981277
>
>
>
> 710250
>
>
>
> 699214
>
> INT_BGR
>
>
>
> 537716
>
>
>
> 562706
>
>
>
> 1446703
>
>
>
> 2046001
>
>
>
> 862377
>
>
>
> 863256
>
> 3BYTE_BGR
>
>
>
> 483275
>
>
>
> 481045
>
>
>
> 1181638
>
>
>
> 1384676
>
>
>
> 651427
>
>
>
> 580961
>
> 4BYTE_ABGR
>
>
>
> 544410
>
>
>
> 499786
>
>
>
> 1292305
>
>
>
> 968783
>
>
>
> 690106
>
>
>
> 683881
>
> 4BYTE_ABGR_PRE
>
>
>
> 504249
>
>
>
> 505588
>
>
>
> 1680086
>
>
>
> 1216445
>
>
>
> 756101
>
>
>
> 687750
>
> USHORT_565_RGB
>
>
>
> 507818
>
>
>
> 505588
>
>
>
> 978153
>
>
>
> 1346746
>
>
>
> 652908
>
>
>
> 655782
>
> USHORT_555_RGB
>
>
>
> 510496
>
>
>
> 509604
>
>
>
> 952272
>
>
>
> 1162004
>
>
>
> 650418
>
>
>
> 670811
>
> BYTE_GRAY
>
>
>
> 481491
>
>
>
> 478367
>
>
>
> 1140585
>
>
>
> 1799231
>
>
>
> 691160
>
>
>
> 583250
>
> USHORT_GRAY
>
>
>
> 506927
>
>
>
> 507373
>
>
>
> 1375751
>
>
>
> 1255267
>
>
>
> 728202
>
>
>
> 646902
>
> BYTE_BINARY
>
>
>
> 541733
>
>
>
> 496217
>
>
>
> 1083466
>
>
>
> 959411
>
>
>
> 730527
>
>
>
> 728461
>
> The changes are tested with plain images having primary colors like
> RED, GREEN, BLUE, BLACK and WHITE.
>
> Thanks,
>
> Jay
>
> -----Original Message-----
> From: Jim Graham
> Sent: Friday, February 12, 2016 4:05 AM
> To: Jayathirth D V; 2d-dev@openjdk.java.net; Philip Race; Prasanta
> Sadhukhan
> Subject: Re: [OpenJDK 2D-Dev] Review Request for JDK-7116979 :
> Unexpected pixel colour when converting images to TYPE_BYTE_INDEXED
>
> Hi Jayathirth,
>
> Did you do any performance analysis of this change? You are adding 6
> tests and multiple branches to per-pixel code.
>
> The effectiveness of this technique depends on the colormap that we
> have set up. For the BufferedImage.TYPE_INDEXED constructor we
> produce a fairly nice colormap, but if someone creates a custom
> colormap then the colors could be anything. We create a decent
> inversion for just about any colormap, but that doesn't mean that
> using only "the best match for solid red" will produce a better result
> for a dithered approximation for red. It is true that if there is a
> really good match for red then we should just use that, but if there
> are no direct matches for red then we may choose to paint a red region
> with solid orange even though there is another color in the colormap
> that when mixed with orange approximates a red tone better. For
> example, if a colormap contains no pure red, but
>
> contains:
>
> 240, 20, 0
>
> 240, 0, 20
>
> (I'm not sure if 20 is within our current error deltas that we use for
> dithering, but this is an example not a test case.)
>
> Then using one of these alone might skew the color towards orange or
> purple. Using both together in a dither pattern might keep the
> overall hue impression as red, but with a small amount of noise in its
> saturation.
>
> What types of colormaps was this tested with?
>
> ...jim
>
> On 2/11/16 6:37 AM, Jayathirth D V wrote:
>
>> Hi,
>
>>
>
>> _Please review the following fix in JDK9:_
>
>>
>
>> __
>
>>
>
>> Bug :https://bugs.openjdk.java.net/browse/JDK-7116979
>
>>
>
>> Webrev :http://cr.openjdk.java.net/~jdv/7116979/webrev.00/
>
>>
>
>> Issue : When Image containing black pixels are converted from any
>
>> format to Byte Indexed format some of the pixels are not black. They
>
>> are following pattern similar to dithering.
>
>>
>
>> Root cause : When we convert any format type to ByteIndexed we are
>
>> adding Error delta values to R,G,B components using dithering indices.
>
>> This is causing some pixels values to not point to proper index in
>
>> color table.
>
>>
>
>> Solution : There is no need to add error delta for primary colors
>
>> containing basic values in R,G,B components. Exclude such pixels from
>
>> delta addition.
>
>>
>
>> Thanks,
>
>>
>
>> Jay
>
>>
>
