I'm looking for a book on Photoshop - 'Inside Photoshop".

In article , Mayayana
wrote:


| The original image is one DIB.
|
| except when it's written for something other than windows.

Woops. Sorry. I should have mentioned that
on a Mac, raster images are actually composed
of 2 parts unicorn and 1 part butterflies.

idiot.

everyone knows it's 1 unicorn and 2 butterflies.

"Eric Stevens" wrote

| What I want to know is when I create a clipping what is
| it that goes on in PS with the basic entities that PS uses to
| manipulate images.
|

Take a simple example of a rectangle. (An
irregular shape would be more complicated.)

You have the original raster image. It's composed
of byte values that represent pixels. In a typical
24-bit image there will be 3 bytes, RGB, per pixel.

First, the editor has loaded the image, which means
reading in the pixel data, which is in rows. For a
100x100, 24-bit color image you have 300 bytes per
row, with 100 rows, to contain the image data.

Now you select a masking area of, say, 20x20
inside that image. To actually work with that area
the editor will need to create another bitmap.
Same bytes, pixels and rows. But this time it
will start (probably) at the top left corner of
the original image and move in to the top left
corner of your masking selection. Then it will
read 20 pixels across (60 bytes) and 20 rows
down. That set of byte values will represent
the mask area.

Now you have an original image and a mask,
which is a second image.

If you look at a BMP file's bytes in a hex editor
you can see how it works. BMP is the simplest
format. There are 54 bytes of file header that
contain info about color depth, size, etc. Then
there are the bytes for pixels. (There's one minor
complication, that rows have to be padded if
necessary to make the number of bytes divisible
by 4, but that's not important to this explanation.)

If you create a white image and save as BMP,
then open it in a hex editor, you can see the pixel
data: FF FF FF FF FF FF
If you then save a red image you can see that:
00 00 FF 00 00 FF starting at the 55th byte.

That's the whole shebang. A graphic editor is
dealing with those byte values.

Some of the Mac users bristle at my use of the
word bitmap, but raster images are the same in
any venue. It's a bitmap. A map, or grid, of color
values, stored as byte data. (Or sometimes
as bit data, as with a 2-color image.)

A RAW is different, but a JPG, PNG, BMP, or
most TIF files are simply raster images,
which are represented by rows of bytes, in a
variety of packages. Once it's opened in a
raster graphic editor it's a byte stream that
represents the pixel grid. The only difference with
Apple is that they tend to use "consumer"
language. Just as Microsoft might describe a
car as a transportation device while Apple might
describe the same thing as "a modern solution to
get where you're going".

You can't look at JPG bytes and see color pixels
because first, there's usually a big header. Then
the actual pixel data is compressed. But once it's
unpacked it's the same thing: A bitmap. A grid
of pixel values stored as byte data.

In article , Mayayana
wrote:

Take a simple example of a rectangle. (An
irregular shape would be more complicated.)

that's what he's asking about.

You have the original raster image. It's composed
of byte values that represent pixels. In a typical
24-bit image there will be 3 bytes, RGB, per pixel.

except when it isn't.

First, the editor has loaded the image, which means
reading in the pixel data, which is in rows. For a
100x100, 24-bit color image you have 300 bytes per
row, with 100 rows, to contain the image data.

it's normally wider for optimization reasons as well as more than 1bpc.

Now you select a masking area of, say, 20x20
inside that image. To actually work with that area
the editor will need to create another bitmap.

nope.

clipping regions are normally paths, not bitmaps, even for simple cases
such as that one.




Some of the Mac users bristle at my use of the
word bitmap, but raster images are the same in
any venue. It's a bitmap. A map, or grid, of color
values, stored as byte data. (Or sometimes
as bit data, as with a 2-color image.)

no, they bristle at your ignorance as well as your anti-apple attitude.


A RAW is different, but a JPG, PNG, BMP, or
most TIF files are simply raster images,
which are represented by rows of bytes, in a
variety of packages.

so is raw.

Once it's opened in a
raster graphic editor it's a byte stream that
represents the pixel grid. The only difference with
Apple is that they tend to use "consumer"
language.

more anti-apple crap.

all companies use consumer language for consumers.

for developers, designers, etc., they don't.

apple in particular uses concepts and terminology well above your pay
grade.

On 2018-03-22 13:44:35 +0000, Mayayana said:

"nospam" wrote

| The original image is one DIB.
|
| except when it's written for something other than windows.
|

Woops. Sorry. I should have mentioned that
on a Mac, raster images are actually composed
of 2 parts unicorn and 1 part butterflies.

Are you still sure of that you're a dude? :-))
--
teleportation kills

On 2018-03-22 14:45:08 +0000, Mayayana said:

A RAW is different, but a JPG, PNG, BMP, or
most TIF files are simply raster images,
which are represented by rows of bytes, in a
variety of packages. Once it's opened in a
raster graphic editor it's a byte stream that
represents the pixel grid. The only difference with
Apple is that they tend to use "consumer"
language. Just as Microsoft might describe a
car as a transportation device while Apple might
describe the same thing as "a modern solution to
get where you're going".

The traditional differences between Macs and PCs are that Macs provide
you with Apple script and, since the introduction of OSX more or less
out of the box shell script functionality. That in conjunction with
that user data mostly are stored in a library folder makes macOS
systems much more effective and manageable. :-)) This could change
though...
--
teleportation kills

In article , android
wrote:

The traditional differences between Macs and PCs are that Macs provide
you with Apple script and, since the introduction of OSX more or less
out of the box shell script functionality. That in conjunction with
that user data mostly are stored in a library folder makes macOS
systems much more effective and manageable. :-)) This could change
though...

no.

On 2018-03-22 19:22:34 +0000, nospam said:

In article , android
wrote:

The traditional differences between Macs and PCs are that Macs provide
you with Apple script and, since the introduction of OSX more or less
out of the box shell script functionality. That in conjunction with
that user data mostly are stored in a library folder makes macOS
systems much more effective and manageable. :-)) This could change
though...

no.

no what?
--
teleportation kills

In article , android
wrote:

The traditional differences between Macs and PCs are that Macs provide
you with Apple script and, since the introduction of OSX more or less
out of the box shell script functionality. That in conjunction with
that user data mostly are stored in a library folder makes macOS
systems much more effective and manageable. :-)) This could change
though...

no.

no what?

no, that's not the 'traditional differences'.

On 2018-03-22 19:43:04 +0000, nospam said:

In article , android
wrote:

The traditional differences between Macs and PCs are that Macs provide
you with Apple script and, since the introduction of OSX more or less
out of the box shell script functionality. That in conjunction with
that user data mostly are stored in a library folder makes macOS
systems much more effective and manageable. :-)) This could change
though...

no.

no what?

no, that's not the 'traditional differences'.

Since the introduction of Windows on PCs it is...
--
teleportation kills

In article , android
wrote:

The traditional differences between Macs and PCs are that Macs provide
you with Apple script and, since the introduction of OSX more or less
out of the box shell script functionality. That in conjunction with
that user data mostly are stored in a library folder makes macOS
systems much more effective and manageable. :-)) This could change
though...

no.

no what?

no, that's not the 'traditional differences'.

Since the introduction of Windows on PCs it is...

no.