ThumbView questions
lazarus / 39-Graphics

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sniperton · 2011-06-14 14:59

Background: I’m a hobby-programmer developing a database application
in which records can contain image-references as well. I use ThumbView
to display referenced images by passing their URLs to the control’s
URLList property. When the user selects a thumbnail, the corresponding
image is displayed in large in a Timage control. At the same time the
user should be allowed to modify the list of referenced images, so
this way ThumbView should serve as a WYSIWYG interface to manipulate
the actual record. Here are my questions:

1. On my 32-bit Win7, ThumbView crashes each time a filename contains
special characters like “á” or “é”. I pass filenames as a simple
string to a TImage (which doesn’t crash) and to a ThumbView (which
crashes with an “exception class ‘FPImageException’ with message: File
‘c:\pic\cézanne.jpg’ does not exist”). ThumbView also crashes if it
reads files ‘on it’s own’, that is when I only specify the directory.
Is this a known bug, and/or is there a workaround for it?

2. As I see ThumbView reads filenames into a StringList which is
sorted by default. It’s handy when someone works with complete
directories, but can be a burden when someone specifies individual
files by their URLs: first because the files are sorted according to
their path, rather than their filename; second because I can no more
identify which thumbnail belongs to which record entry. Or can I? Or
is it possible to easily switch off the sorting feature?

3-4. Two more related questions. The SelectedItem method returns an
individual item’s URL as I see, but is there a possibility to access
an item from code? (I mean by its index within the URLList, or
something like that.) And is it/could it be possible to add an object
(a string or an integer) to the URL (like with a TlistBox)?

Thanks for your attention, and thank to theo for this great component,
cheers

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theo · 2011-06-14 17:44

1. Should work now, download again:
http://www.theo.ch/lazarus/thumbview.zip
2. Comment calls to fMngr.Sort(0); in the source code
(thumbcontrol.pas)
3. You have the source code. Do with it what you like ;-)

For example you can get the Image from mouse-coords like this

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.ThumbControl1MouseMove(Sender: TObject; Shift: TShiftState; X, 
Y: Integer);var itm:TThreadedImage;begin itm:=ThumbControl1.ItemFromPo
int(Point(x,y)); if assigned(itm) then Caption:=itm.URL;end;

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sniperton · 2011-06-15 13:18

Thanks a lot, theo!