ImmutableBitmap = 3

General
1

I wanted to know whatkind of object I have in the code below, but the debugger says:

Picture ImmutableBitmap = 3

Used code:

[code]Dim Clip As New Clipboard

If Clip.PictureAvailable Then // Break Point set here
If Clip.RawDataAvailable(“public.png”) Then[/code]

I have searched the LR and found:

http://documentation.xojo.com/api/graphics/picture.html#picture-type

But no explanation for the Integer value (here: 3).

I know (because I checked with AppleScrips) I have a png Class in the Clipboard.

Why did I searched ? Because the pasted image holds:

{{TIFF picture, 30022}, {«class 8BPS», 309676}, {GIF picture, 20599}, {«class jp2 », 26308}, {JPEG picture, 15824}, {«class PNGf», 39933}, {«class BMP », 1069034}, {«class TPIC», 240586}}

and I get an UnsupportedOperationException while using RGBSurface (elsewhere in the Project). The file loaded from disk does not behave this Exception. So, I suppose Xojo gets the image’s first Class (a TIFF image), so I directed my code to get the png Class image instead (a bit more complex to get).

The message I get is:

[b]An exception of class UnsupportedOperationException was not handled. The application must shut down.[/b] Exception Message: Cannot modify a read-only image

2

I seem to recall that pictures loaded from a file are immutable (they cannot be changed directly), hence the Exception when using RGBSurface.

Try creating another picture object, and drawing the loaded picture into that

3

Documenetation seems screwy - for example the information you want should be here: http://developer.xojo.com/hidpi-support but the website is redirecting to the home page.

Edit: it’s found here: https://documentation.xojo.com/topics/graphics/hidpi_support.html

I emailed docs@xojo.com about the URL problems.

4

Thank you for your answers.
My question was bad written because I do not get the answer I was awaiting.

a. The question is not about an ImmutableBitmap image that can or cannot be changed, but what means a value of 3 (three).

b. Your first URL is not bad, but it does not have the correct casse…
I do not readed yet the text @ provided link, but I do not know what HIDPI Support have to do here.
I’m going to read the page.

5

In http://documentation.xojo.com/api/graphics/picture.html#picture-type , I was awaiting some explanation for:

ImmutableBitmap = 1 Explanation for integer value 1 ImmutableBitmap = 2 Explanation for integer value 2 ImmutableBitmap = 3 Explanation for integer value 3 ImmutableBitmap = 4 Explanation for integer value 4

These value are what I get in the debugger, so some explanation are needed.

And, in fact, what I was searching is the type of the Picture: png, tiff, jpeg, bmp and so on…

6

Its JUST the value of the specific value of the enum
http://documentation.xojo.com/api/graphics/picture.html#picture-types
there is no “meaning” other than “its an immutable bitmap”

Dim p1 As Picture.Types
Dim p2 As Picture.Types
Dim p3 As Picture.Types
Dim p4 As Picture.Types

p1 = Picture.Types.Image
p2 = Picture.Types.ImmutableBitmap
p3 = Picture.Types.MutableBitmap
p4 = Picture.Types.Vector

break

the explanation is “this is an image type that you cant change - its immutable”

its NOT the image format (png, jpeg, etc)

7

Thank you Norman for the explanation. It now is clear on both what Types is and how/why to use it.

BTW: my focus was at 200% in my problem and I do not understand (skip the word) Enum from the page (I printed it to pdf 'cause my internet access is very, very slow).

That is not what I was seeking. I am actually doing something else, I will come back to this when I will have enough of the current things :wink:

Ah ! I remember now what I was doing when I was stopped in my tracks. I will add a note afaic before I forgot ;).

8

once you have an image In memory there is no “picture format”
its a “picture” and quite generic
but you CAN tell from the file you opened to read it what the image format is as that folderitem has a “type” that should match one of your defined filetypes (http://documentation.xojo.com/api/files/folderitem.html.Type)

9

My question was a bit long and complex.

I noticed that when I put with a Paste an image in a Canvas, I get a crash. When I load that very same image, I do not have that crash.

The crash appears in the use of a RGBSurface.

Some days ago, I noticed that the Picture (inside the running application) have to have a Graphics “part”. So, I started to explore what I have in my Clipboard and my clipboard is full of different images Classes (tiff / png / etc. read the original question). So I took the image in the png class (or format or…) from the Clipboard. The problem still arise.

Here the code I use:

[code]Dim Clip As New Clipboard

If Clip.PictureAvailable Then
If Clip.RawDataAvailable(“public.png”) Then
Dim Pict_MB As MemoryBlock
Dim Clip_Pict As Picture

// Paste the PNG available Picture
Pict_MB = Clip.RawData("public.png")
cImage.Backdrop = Picture.FromData(Pict_MB)

Clip_Pict = New Picture(cImage.Backdrop.Width, cImage.Backdrop.Height)
Clip_Pict.Graphics.DrawPicture Picture.FromData(Pict_MB),0,0
cImage.Backdrop = Clip_Pict

// Set a Copy in Offscreen_Pict
Offscreen_Pict = Clip.Picture

Else
// Paste the available Picture
cImage.Backdrop = Clip.Picture

// Set a Copy in Offscreen_Pict
Offscreen_Pict = Clip.Picture

End If
End If

// Close the Clipboard instance
Clip.Close[/code]

Later, I use RGBSurface (.Pixel) and get a crash as I explained far above (UnsupportedOperationException).

On El Capitan / current Xojo.

10

I don’t see where you are creating a “mutable” picture

clip.picture is immutable, and setting offscreen=clip does nothing but make a copy of the pointer, it doesn’t change any attributes

11

I too do not understand…

I’ve added a break point in the first If line of the shared code above and follow step by step. I looked carefully the Debugger and saw ImmutableBitmap = 3; because I do not knew the meaning of the 3 value, I asked here.

Hours after that I wrote:

Clip_Pict.Graphics.DrawPicture Picture.FromData(Pict_MB),0,0

RGBSurface is meant to work on Clip_Pict, but no.