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Just What is a Bitmap?



 
 
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  #1  
Old December 1st 18, 10:18 PM posted to rec.photo.digital
RichardLamprey
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Posts: 4
Default Just What is a Bitmap?

When someone says "use a jpeg bitmap", what do they mean?

Googling for how to create a jpeg bitmap says it's pretty much anything
https://www.techwalla.com/articles/h...reate-a-bitmap

Microsoft thinks a jpeg bitmap is something specific
https://docs.microsoft.com/en-us/dot...ap-at-run-time

Artists maybe create jpeg bitmaps by hand?
https://magazine.art21.org/2011/09/1.../#.XAL5P9NOk4k

Programmers maybe create jpeg bitmaps from text files?
https://social.msdn.microsoft.com/Fo...ng-a-text-file

Diehards even seem to be using hex editors to make jpeg bitmaps
https://www.quora.com/How-can-I-make...g-a-hex-editor

I'm not asking about bmp file format but about bitmaps in jpeg format.
What is a bitmap jpeg file anyways?
  #2  
Old December 1st 18, 11:45 PM posted to rec.photo.digital
Neil[_9_]
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Posts: 418
Default Just What is a Bitmap?

On 12/1/2018 4:18 PM, RichardLamprey wrote:
When someone says "use a jpeg bitmap", what do they mean?

Googling for how to create a jpeg bitmap says it's pretty much anything
https://www.techwalla.com/articles/h...reate-a-bitmap

Microsoft thinks a jpeg bitmap is something specific
https://docs.microsoft.com/en-us/dot...ap-at-run-time

Artists maybe create jpeg bitmaps by hand?
https://magazine.art21.org/2011/09/1.../#.XAL5P9NOk4k

Programmers maybe create jpeg bitmaps from text files?
https://social.msdn.microsoft.com/Fo...ng-a-text-file

Diehards even seem to be using hex editors to make jpeg bitmaps
https://www.quora.com/How-can-I-make...g-a-hex-editor

I'm not asking about bmp file format but about bitmaps in jpeg format.
What is a bitmap jpeg file anyways?

Perhaps it would help to separate the two terms. To answer the general
question, a 'bitmap' is an image comprised of squares arranged in rows
and columns.

JPEG is a file format that contains a version of the original bitmap
image and organizes aspects of the image such as its resolution relative
to the original, file size and other factors. One original purpose of
the jpeg format was to allow journalist photographers to send images
across the internet when 300bps modems were commonplace.

--
best regards,

Neil
  #3  
Old December 2nd 18, 12:08 AM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 22,119
Default Just What is a Bitmap?

In article , RichardLamprey
wrote:

When someone says "use a jpeg bitmap", what do they mean?


they mean a jpeg image.

what you mean is trolling.
  #4  
Old December 2nd 18, 01:49 PM posted to rec.photo.digital
Carlos E.R.
external usenet poster
 
Posts: 157
Default Just What is a Bitmap?

On 01/12/2018 23.45, Neil wrote:
On 12/1/2018 4:18 PM, RichardLamprey wrote:
When someone says "use a jpeg bitmap", what do they mean?

Googling for how to create a jpeg bitmap says it's pretty much anything
https://www.techwalla.com/articles/h...reate-a-bitmap

Microsoft thinks a jpeg bitmap is something specific
https://docs.microsoft.com/en-us/dot...ap-at-run-time


Artists maybe create jpeg bitmaps by hand?
https://magazine.art21.org/2011/09/1.../#.XAL5P9NOk4k


Programmers maybe create jpeg bitmaps from text files?
https://social.msdn.microsoft.com/Fo...ng-a-text-file


Diehards even seem to be using hex editors to make jpeg bitmaps
https://www.quora.com/How-can-I-make...g-a-hex-editor


I'm not asking about bmp file format but about bitmaps in jpeg format.
What is a bitmap jpeg file anyways?

Perhaps it would help to separate the two terms. To answer the general
question, a 'bitmap' is an image comprised of squares arranged in rows
and columns.

JPEG is a file format that contains a version of the original bitmap
image and organizes aspects of the image such as its resolution relative
to the original, file size and other factors. One original purpose of
the jpeg format was to allow journalist photographers to send images
across the internet when 300bps modems were commonplace.


I'm unsure a jpeg can be considered a format usable for bitmap
manipulation, because it is a lossy format. So someone creating or
changing a bitmap would not use jpeg because individual pixels can
change or just be lost. A bunch of spatially contiguous pixels can be
grouped and get the same value - when in the original they were different.

--
Cheers, Carlos.
  #5  
Old December 2nd 18, 04:08 PM posted to rec.photo.digital
nospam
external usenet poster
 
Posts: 22,119
Default Just What is a Bitmap?

In article , Carlos E.R.
wrote:

I'm unsure a jpeg can be considered a format usable for bitmap
manipulation, because it is a lossy format. So someone creating or
changing a bitmap would not use jpeg because individual pixels can
change or just be lost. A bunch of spatially contiguous pixels can be
grouped and get the same value - when in the original they were different.


of course it's usable. it's done every day.

it's obviously preferable to use raw, but not required.
  #6  
Old December 2nd 18, 05:03 PM posted to rec.photo.digital
Neil[_9_]
external usenet poster
 
Posts: 418
Default Just What is a Bitmap?

On 12/2/2018 7:49 AM, Carlos E.R. wrote:
On 01/12/2018 23.45, Neil wrote:
JPEG is a file format that contains a version of the original bitmap
image and organizes aspects of the image such as its resolution relative
to the original, file size and other factors. One original purpose of
the jpeg format was to allow journalist photographers to send images
across the internet when 300bps modems were commonplace.


I'm unsure a jpeg can be considered a format usable for bitmap
manipulation, because it is a lossy format. So someone creating or
changing a bitmap would not use jpeg because individual pixels can
change or just be lost. A bunch of spatially contiguous pixels can be
grouped and get the same value - when in the original they were different.

That is a different issue. There are several lossy bitmap formats, one
of which is jpeg. Sometimes its lossy aspect matters, sometimes not.

--
best regards,

Neil
  #7  
Old December 2nd 18, 11:17 PM posted to rec.photo.digital
Carlos E.R.
external usenet poster
 
Posts: 157
Default Just What is a Bitmap?

On 02/12/2018 17.03, Neil wrote:
On 12/2/2018 7:49 AM, Carlos E.R. wrote:
On 01/12/2018 23.45, Neil wrote:
JPEG is a file format that contains a version of the original bitmap
image and organizes aspects of the image such as its resolution relative
to the original, file size and other factors. One original purpose of
the jpeg format was to allow journalist photographers to send images
across the internet when 300bps modems were commonplace.


I'm unsure a jpeg can be considered a format usable for bitmap
manipulation, because it is a lossy format. So someone creating or
changing a bitmap would not use jpeg because individual pixels can
change or just be lost. A bunch of spatially contiguous pixels can be
grouped and get the same value - when in the original they were
different.

That is a different issue. There are several lossy bitmap formats, one
of which is jpeg. Sometimes its lossy aspect matters, sometimes not.


If you are going to do bitmaps, and expect the pixels to stay the
*exact* same the next time you open the file, don't use a lossy format,
because it can change your pixels...

--
Cheers, Carlos.
  #8  
Old December 3rd 18, 01:53 AM posted to rec.photo.digital
Neil[_9_]
external usenet poster
 
Posts: 418
Default Just What is a Bitmap?

On 12/2/2018 5:17 PM, Carlos E.R. wrote:
On 02/12/2018 17.03, Neil wrote:
On 12/2/2018 7:49 AM, Carlos E.R. wrote:
On 01/12/2018 23.45, Neil wrote:
JPEG is a file format that contains a version of the original bitmap
image and organizes aspects of the image such as its resolution relative
to the original, file size and other factors. One original purpose of
the jpeg format was to allow journalist photographers to send images
across the internet when 300bps modems were commonplace.

I'm unsure a jpeg can be considered a format usable for bitmap
manipulation, because it is a lossy format. So someone creating or
changing a bitmap would not use jpeg because individual pixels can
change or just be lost. A bunch of spatially contiguous pixels can be
grouped and get the same value - when in the original they were
different.

That is a different issue. There are several lossy bitmap formats, one
of which is jpeg. Sometimes its lossy aspect matters, sometimes not.


If you are going to do bitmaps, and expect the pixels to stay the
*exact* same the next time you open the file, don't use a lossy format,
because it can change your pixels...

Why are you under the impression that I disagree that jpeg is lossy, or
is it that you think that's *always* the most important aspect of an
image? Just curious.

--
best regards,

Neil
  #9  
Old December 5th 18, 03:46 PM posted to rec.photo.digital
Carlos E.R.
external usenet poster
 
Posts: 157
Default Just What is a Bitmap?

On 03/12/2018 01.53, Neil wrote:
On 12/2/2018 5:17 PM, Carlos E.R. wrote:
On 02/12/2018 17.03, Neil wrote:
On 12/2/2018 7:49 AM, Carlos E.R. wrote:
On 01/12/2018 23.45, Neil wrote:
JPEG is a file format that contains a version of the original bitmap
image and organizes aspects of the image such as its resolution
relative
to the original, file size and other factors. One original purpose of
the jpeg format was to allow journalist photographers to send images
across the internet when 300bps modems were commonplace.

I'm unsure a jpeg can be considered a format usable for bitmap
manipulation, because it is a lossy format. So someone creating or
changing a bitmap would not use jpeg because individual pixels can
change or just be lost. A bunch of spatially contiguous pixels can be
grouped and get the same value - when in the original they were
different.

That is a different issue. There are several lossy bitmap formats, one
of which is jpeg. Sometimes its lossy aspect matters, sometimes not.


If you are going to do bitmaps, and expect the pixels to stay the
*exact* same the next time you open the file, don't use a lossy format,
because it can change your pixels...

Why are you under the impression that I disagree that jpeg is lossy, or
is it that you think that's *always* the most important aspect of an
image? Just curious.


Maybe language issue? Or cultural differences?

To me a _bitmap_ has to transferred exactly, and jpeg is not valid for
bitmaps.

--
Cheers, Carlos.
 




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