I want to store small bitmaps in a text file similar to the way Delphi does it with it's dfm files.
Is there a function in the RTL or VCL that I could use to do this?
I suggest that you do the following:
Save to an in memory stream. Use TMemoryStream, and call SaveToStream on the bitmap.
Compress the stream, perhaps using the zlib unit. This step is optional.
Encode the stream using base64. For example you can use the functionality provided by Soap.EncdDecd.
And in the opposite direction, well you just reverse the steps.
Textual DFMs use the BinToHex() function to format binary data.
You can simply use Win32.WriteFile to write your bitmap-buffer into a file.
Related
Is there a way I can use coding
Memo1.lines.savetofile ('textfile1.txt') without it then deleting whatever already is in the texfile to save the memos lines?
Create a TFileStream that opens the existing file, seek to the end of the stream, and then pass the stream to Memo1.Lines.SaveToStream().
Presumably you want to append the text to the file. Do that like so:
TFile.AppendAllText(FileName, Memo1.Text);
This uses the TFile class from the IOUtils unit. Pass an encoding parameter if you want to exercise control over the encoding used.
I am writing a program in Delphi which should get the date and time of the picture which was taken with photo cam and then it would rename the file to include the date+time it found.
So far i have achieved that by opening file as binary and searching for a special order of bytes. These bytes were then followed by the date and then time. So i've come to a problem. Actually few problems.
Because it reads the file 1 byte after another, reading a file is a slow process. If the date was found, it is usually at the start of file, it doesn't take long, however if 'special byte order' was not found, it will read the whole file. So my method is way too slow.
The special byte order may change in some pictures (i have no idea why) even if it was taken with the same camera. So my program sometimes fails to find the date in the file even though it is there.
Windows explorer has no problems finding date in all of the pictures, so i was thinking maybe there are some kind of special functions which could get me what i need?
How do i get the information i need from the picture so it works with all the formats?
Thanks
I think you only need to look at the EXIF information. http://en.wikipedia.org/wiki/Exif
There are some open source tools which accomplish that, but I don't know of anything Delphi specific. If you're not scared of Java, you can have a look at the source code of this open source project: http://sourceforge.net/projects/jexifviewer/ to see how they evaluate the date field.
You can then optimise your reader, to only look at the relevant area. You might want to keep in mind that the Endianness in Java is different to Delphi.
Jules is right about Exif data; you might want to try this Delphi library:
http://delphihaven.wordpress.com/ccr-exif/
This is an amazing site to view Exif data.
http://regex.info/exif.cgi
If it is a graphic file (as in your case), to open it with a dialog box, place a TOpenPictureDialog component on the form.
Also place the component TLabel, for displaying the date of creation of the file.
In the button's place the following code:
if OpenPictureDialog1.Execute then Label1.Caption := DateTimeToStr(FileDateToDateTime(FileAge(OpenPictureDialog1.FileName));
In order to open jpeg and png files in the code, in the line uses you need to add the name of the two libraries, JPEG, PNGImage.
If you have the full address of your file, you can write the code above instead of the code above:
Label1.Caption := DateTimeToStr(FileDateToDateTime(FileAge('full address to file')));
If you only need the date, without the file creation time, then instead of the DateTimeToStr command, use the DateToStr command.
It's easy to convert from cur-file to bitmap, using the LoadCursorFromFile API call and calling DrawIcon(..., hCursor) on that bitmap.
But how can I load it from stream without too much handcoding and convert into TBitmap?
There is an MSDN library article that describes the .cur and .ico file formats in great detail. It's pretty easy – I wrote some Delphi code to read .ico files not so long ago using this article as my reference.
Use Kicon.
i made a simple form designer in delphi, drag and drop a button on the form and it draws it, but the thing is i cant save/load this project since i dunno how to, is there anyway that i could be abel to save it to .rc file and load it from there?
That depends how you programmed your form designer. In forms created in Delphi's designer all components (and subcomponents) are referenced from TForm.Components array property. All controls are also referenced in TForm.Controls array property (if you remove an container control, all it's subcontrols are destroyed too).
If you have followed that pattern, all you have to do is monitor additions to the TForm.Components array (maybe using an overriden TForm.Notification method) and using this data to build your persistent form's file.
The VCL contains methods for using its builtin DFM support. There is a sample in the Delphi 2009 documentation for ObjectBinaryToText; I guess this works for D7 too. And IIRC there already was a code fragment for ComponentToString in the D5 help - search for ObjectBinaryToText.
Delphi stores form layout in *.dfm file. You can use it's structure to save your projects. File is textual and readable by humans. It is not hard to parse file like that rading one line by one. If you need more help, ask for it.
You can use something like delphi .DFM. Counting all objects and then read their attributes and write them into a file. Example Code:
For i:0 To Form1.ComponentsCount-1 Do Begin
// Read Component Attributes And Write Them In Your Format
End;
If you just want to save the form you designed in your designer, use something like TFileStream to create the RC file when the user saves. You might be better off with your own file format for your forms, with the option to export as an RC file, as RC files arent really meant to useful for storing any design time info you may need.
how to read data from .dat files ?
i just tried like this memo1.lines.loadfromfile('c:\myfile.dat'); but not worked
Note : File type is binary
can any one please help me :)
#radick to show the contents of an binary file in a memo control you must encode o convert the data to valid ASCII characters, to turn it all into text. because you can not load something that is not text into a text control.
you can find a very nice sample from Peter Below in this link.
read a binary file and display the byte values as ASCII?
(source: swissdelphicenter.ch)
Use the TStream descendants from the VCL Classes unit to read binary files.
There are plenty Delphi TStream reading binary files examples you can find using Google.
--jeroen
You might look at this post as they seem to be discussing this very thing.