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Gianstefano Monni
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 Posted: Tue Jul 01, 2003 3:04 pm Post subject: TImage subclass |
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Hi,
I hope this is the right newsgroup to post my question.
We've developed a medical application, and we need to use a custom image
format (we call it "Zbi" format). Right now, we've developed a ZbiClass that
reads/writes bytes stream and we show them with StretchDIBits function, but
we'd like to have a "TZBIImage:TImage" class capable of reading/writing
images in Zbi format, and to show them in a form. I suppose I need to
subclass TImage, but I have no documentation on which methods I must
override, and so on... I would like to have some suggestions, links, ideas
Thanks in advance
Gianstefano Monni
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Damon Chandler (TeamB)
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| Posted: Sat Jul 05, 2003 3:33 am Post subject: Re: TImage subclass |
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Gianstefano,
| Quote: | We've developed a medical application, and we need to use a custom
image format [...] we'd like to have a "TZBIImage:TImage" class capable
of reading/writing images in Zbi format, and to show them in a form.
|
If you need only to display the Zbi images at run time, then all you need to
do is convert from your format to a bitmap; specifically, you'd create a
TBitmap object of the correct dimensions, and then use the TBitmap::ScanLine
property to copy your raw array to the pixels of the bitmap--see the
ConstructBMP() function in this post http://tinyurl.com/g2g9. (You may also
need to use the SetDIBColorTable() Win32 function if the pixel values denote
color-table indices.) Instead of ScanLine, you could alternatively write to
a stream a properly initialized BITMAPFILEHEADER struct followed by your DIB
data (BITMAPINFO data + pixels), and then you'd use the
TBitmap::LoadFromStream() method to construct the bitmap--see
http://tinyurl.com/g2g4.
If you need to display your Zbi images at design time, then you'll need to
use the TPicture::RegisterFileFormat() member function. In this case, your
TZBIImage class should be a TGraphic descendant.
Good luck,
--
Damon (TeamB)
BCBCAQ - http://bcbcaq.bytamin-c.com
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Gianstefano Monni
Guest
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| Posted: Wed Jul 09, 2003 2:12 pm Post subject: Re: TImage subclass |
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Hi,
thanks for your answer,I'm trying to sum up all the tips (I've posted the
question in vcl.componens.writing and graphics groups), and... I feel a bit
confused now
I mean, now I know I've to subclass TGraphic, and I must override some
methods of the class: in particular I must override
1. Assign
2. LoadFromStream: I must load data from a stream, unzip it (right now I'm
using zlib and it works as expected)
3. SaveToStream: I must save bitmap data and other medical data in a stream
filtering them with zlib
Could you tell me if I must use a private buffer, or there's a kind of
standard buffer to save this data ? I mean, TImage class use Pixels property
and ScanLine abstraction, there's something similar to use with TGraphic
class or I must implement it on my own ?
I have to
"Damon Chandler (TeamB)" <dmc27 (AT) cornell (DOT) edu> ha scritto nel messaggio
news:3F0646FF.5CCB9664 (AT) cornell (DOT) edu...
| Quote: | Gianstefano,
We've developed a medical application, and we need to use a custom
image format [...] we'd like to have a "TZBIImage:TImage" class capable
of reading/writing images in Zbi format, and to show them in a form.
If you need only to display the Zbi images at run time, then all you need
to
do is convert from your format to a bitmap; specifically, you'd create a
TBitmap object of the correct dimensions, and then use the
TBitmap::ScanLine
property to copy your raw array to the pixels of the bitmap--see the
ConstructBMP() function in this post http://tinyurl.com/g2g9. (You may
also
need to use the SetDIBColorTable() Win32 function if the pixel values
denote
color-table indices.) Instead of ScanLine, you could alternatively write
to
a stream a properly initialized BITMAPFILEHEADER struct followed by your
DIB
data (BITMAPINFO data + pixels), and then you'd use the
TBitmap::LoadFromStream() method to construct the bitmap--see
http://tinyurl.com/g2g4.
If you need to display your Zbi images at design time, then you'll need to
use the TPicture::RegisterFileFormat() member function. In this case,
your
TZBIImage class should be a TGraphic descendant.
Good luck,
--
Damon (TeamB)
BCBCAQ - http://bcbcaq.bytamin-c.com
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