I am looking to build my own component and have no idea where to begin. I have some Delphi books but they are old and outdated, and am looking for some recommendations on tutorials/books to help me do this. The component will be pretty simple, basically 2 labels and an image. I need hundreds of these in an array, so I thought a component would be the best route. The text will adjust based on width etc, and have some mouseover events. So basically, where do I begin?
I am using Delphi 2009, this will be a win32 app.
Thanks!
You can order Ray Konopka's book Dev. Custom Delphi 3 Components - PDF for 25$. It's a specialized book on the subject and very good for a beginner too.
The main principles behind developing components is:
Whether the component is visual or
not (Does it need a Canvas to paint on)
Does it need a window handle or not (visual or non-visual)
Once you answered those questions you can look at Delphi's source code for examples.
As far as I know, Delphi Component Design, by Danny Thorpe, is still the best book on the subject. Component design hasn't changed significantly in the last 15 years, so whatever books you have probably aren't as outdated as you think. There are three things to keep in mind while reading older references:
Names of certain units have changed. There's no DsgnIDE anymore, for example. It's DesignIDE instead.
Design-time code is strictly separated from run-time code now. This means you can't use DesignIDE in your component's unit, or else you're barred from using run-time packages. Older Delphi versions didn't have this technical restriction (although it's always been a legal restriction), so old code examples you find might need to change a little bit.
Strings are Unicode now, so as with all old code examples you find, there might be some invalid assumptions about character sizes that you'll need to recognize.
The biggest obstacle to writing components is that you're expected to use various protected members of the classes you descend from, but those frequently aren't documented, so you'll have to be much more willing to go read the VCL source code for examples of how various methods are used.
The easiest way to do what you want is to create a new form. Drop the labels and image and arrange them the way you want; if it suits your need, put them on a panel so they can be moved around as a unit.
Select all the components you want included (and including the panel if you chose to use one), and then click the Component item on the IDE's main menu, and select the "Create Component Template". (It's only enabled if you have selected components on the current form.) A dialog will appear asking you for a name for the new component, and the Component Palette page on which you want it to appear.
Take a look at this article, which describes how to build new components made up of a group of existing components.
Don't worry about your books being old.
Just about everything from the old days still works fine and what little doesn't is generally due to name conflicts or the addition of Unicode in the 2009 version.
They aren't Microsoft, they don't go breaking old code without good reason. In fact, take some code from the old DOS days--assuming it doesn't try to manipulate the screen it's likely to run with minimal fixup.
Don't worry about your old books! Since v3, Delphi hasn't changed much. This is why most of the programs compiled with D3 still compiles in D7 or even newer versions. And if it doesn't compile, probably you need to change a line or two, here and then.
I would recommend you to search other VERY simple components on Internet and see how they are made. Then make your own and post it here. Let other take a look at it and suggest improvements or spot bugs.
About your control's design:
1) maybe you DON'T need those two labels. You can just paint the text directly on the image. If you have lots of those components as you say, you may save a little bit of memory.
2) you may NOT want to have lots and lots and lots of images loading in one form. The overhead may be significant. What you can do is to load the pictures ONLY in images that are visible on screen - and you will put on screen ONLY 5-10 images (or whatever number of images you can show on the form without going out of screen). As the user scrolls down, you keep the same same TImage controls on screen but you load new (next) images in them.
3) You may not want to store labels and TImage in an array (I suppose it is an TImage because it seems you want to show them on the screen else you won't need labels - you need to explain your problem in more details if I got it wrong). But you can store a TBitmap and the text (that you want to display in labels) instead.
So, you may need to calculate how much CPU/disk overhead your hundreds of controls will create and how much memory they need. If you stay well under 1GB and the loading time is under 10 seconds, then it is relatively ok. IF not, you may want to think about your control's design before starting to actually implement it.
Hope this was helpful.
See ya.
Related
Does it happen that no one ever needs histogram in Delphi ?
Google gave me a bunch of half-baked code snippets. But it means that each time you need one - you have to invent one more ad hoc bycicle.
Torry mostly told me about some very expensive closed source Math Statistics or Financial packages, that as a subproduct have histograms. But they are very expensive and since you have no source code, each time you install update onto IDE/RTL/VCL you're probably screwed, until the vendor would make (soon ? ever?) updated packages. Given thatvendor is still does exists.
S.O. told me nothing, nil.
For what i found...
Mitov.com provides some histograms in PlotLab. which told to be free for non-commercial. Alas, it is again closed-source, and if the Histogram - quite fancy let's admit -is the onlything i need from it - why pay the whole price ?
One more example http://DSpatial.sf.net
Just few years ago i used it in Delphi 5, but even then i felt the author is loosing interest in the project. I made few enhancement, fixed some bugs, he merged them and that's all. The component was not very useful and lacked upon features, yet better than nothing. Now the project seems to be completely dead. Good old days, etc. But i do not want them back :-)
And Stack Overflow seemingly carries no single question about it. But maybe just no one bothered to create topic, after search found nothing ? I mean, Delphi was created for database access, histograms are one of basic ways to visualize data, and no one crosses them ? Something with nice style, with rich mouse tooltip like in HTML/CSS/JS on http://www.moskva.fm/stations/FM_95.2 ?
Or is this too domain-related and not ever possible to have good abstraction ?
TChart is a control that ships with most versions of Delphi. TChart can be used to make histograms (bar charts) in style. The following give you some ideas about how to use it: http://www.digitalcoding.com/tutorials/delphi/Simple-steps-to-create-Delphi-chart.html and http://delphi.about.com/od/adptips2006/qt/chart_selectbar.htm .
If you need something with code, google the pages at delphiforfun.org/programs/oscilloscope.htm . These are not controls. The oscilloscope article has a histogram with source. Some of the other projects at the site have other histogram graphs with source..not elegant but useful and free. Use them as a template to make your own control.
The link at http://delphiforfun.org/programs/Math_Topics/probability_distributions.htm shows how to make your own statistics displays with "histograms." This example makes use of TChart.
Here is some more stuff to try I found looking at my resource file:
http://wiki.lazarus.freepascal.org/TAChart, http://members.home.nl/mvanwesten/en_lazarus.html , http://www.martinole.org/TAChart.html ...some of these are GPU components that supposedly work with some versions of Delphi. Perhaps this is your lucky day as there is some source code. The first and third listed probably will work reasonably for histograms. You may have to write your own statistics algorithms.
Found this thread while doing some searching. The ImageEn component suite has a THistogramBox component. It's the NOT prettiest thing in the world, but it's the only one I've found so far.
http://www.imageen.com
I came across a histogram example in a gdiplus package available for download from code central. I don't know if it will do what you need but when I saw it I remembered your SO question.
HTH.
If you were using firemonkey, you could just created a series of TRectangles in series. They can be made unclickable by turning hittest off. Or is that too easy and straightforward?
I need to improve a screen in our Application that presents an HMI (Human Machine Interface) display embedded in our Delphi code. This screen provides our customer with the ability to perform a range of actions (run test, product report etc) and to expose and view key named data values. This customisation is required because our Application controls machinery that might be operated by a range of skill levels from simple operator (may not speak English and must have very limited control) through to a power user who wishes to 'see everything' and have max control.
Some years back I created a solution based on an embedded HTML viewer (Turbopower's as it was then) and TPageProducer to dynamically tweak an HTML template (that the user could customise) and which would display a simple set of controls and data tables. This works fine but is slow to edit (you have to tweak the template and look-see the effect) and I'm sure there are better ways now.
What I need is similiar to a Delphi form that can be customised at runtime. I need: buttons, labels and edits. Editable shapes and arrows are desireable as are fixed images over which controls and text can be laid. The layout should be saveable (like a DFM file) and text labels should be of two types - fixed text and those which update to display key values on an update notification (like a DB control would). The final layout should zoom its scale to fit a resizable layout.
This question is about the best tool for the job and I'm not coming into this totally cold, I've experimented with Greatis Form Designer and obtained a working solution but before I commit, I would apprecaite comments about whether a report tool (with built-in report editor) would be possible / useable / better since a print dump feature would also be useful. (Fast Reports? Quick Report etc?). Note though that this is a display requirement primarily. Comments re newer embedded HTML solutions would also be welcome as would anything to ensure max future-proofing of the layout format.
Any solution should be useable in Dephi 7 (for now!) and does not need to be unicode as long as there is a migration path to this for newer Delphi's.
Any other comments or observations would be very welcome. Thanks.
Have you looked first at the free JVCL stuff? There's a JvInspector (RTTI component property inspector, just like Delphi property inspector), and a form designer, and so on. You could roll your own solution based on these, and even use JvInterpreter for some scripting capability.
Secondly, if you can support ANY control that you have, in your designer, and you need some HMI specific stuff, check out IOCOMP: http://www.iocomp.com/
TMS Scripter Studio Pro provides a Delphi-like IDE and form designer with scripting, but it maybe overkill for your requirements.
It seems that most Delphi applications fit into two classes: Database-centric Applications that use Reporting Systems for all their printing needs, and applications that don't need printing.
For those in the excluded middle (non-database printing, non-reporting system), there are components to help out. For example, I have been a Developer Express "Express Printing System" customer since early on in that product's life cycle. For printing out any component (grid, spreadsheet,etc) that is also a Developer Express Printing System component to help me out.
So far so good. What I'm looking for is an alternative way (in Delphi 2010) to generate one or two page printouts that contain, typically:
Titles, and Headings
Page Headers and Page Footers
Ability to include a large picture which is the primary thing on the page. In this case, the picture (bitmap) is a chart custom drawn by me.
100% bulletproof output quality on every version of windows known to human kind, with every kind of printer known to human kind.
[UPDATE: I was previously having bizarre glitches with Developer Express printing components on color laser printers, which I am now quite hopeful I can sort out. ] ... Still I think it would be wise to look at other printing components out there so my "toolbox" of possible solutions for my current and future projects can include a simple reliable way of generating printer pages.
So I could really use suggestions. I am biased against Reporting Systems, even Code Based ones, but I am considering fast reports even though my use for it would be far from the typical use-case scenarios. There are no row and column data-sets involved in my printed pages.
Update/Final: It looks like FastReports is great. It can easily transfer any data from in memory in your application (such as an Image), to the current report page(s), like this:
procedure TForm2.Button1Click(Sender: TObject);
var
pic:TfrxPictureView;
begin
pic := frxReport1.FindObject('Picture1') as TfrxPictureView;
pic.Picture.Assign(Image1.Picture);
frxReport1.ShowReport;
frxReport1.Print;
end;
Fast Report is suited my needs very well. They even have a scripting system. You could try if is good enough for you.
http://fast-report.com/en/
I have been using the HtmlViewer component from www.pbear.com for all my printing solutions.
You have to create an html page (or two pagews) of course, but once you can do that, you can do anything you like (or at least what the html standard supplies). The HtmlViewer has a preview window so that can be used as a generic 'report' viewer and it can print the output immediatly.
You will be amazed what you can do with html, and it is easy to change the 'report' because it's just plain html.
If you should go that way, I will be happy to assist you in any question you might have. The component is free since a couple of years. So that could be an easy and inexpensive solution to your problem.
What's the best way to draw shapes interactively at run time using Delphi? I need to be able to select, drag and resize the shapes. This will be used to mark up existing images and documents.
This looks like a good starting point, but I'm wondering if there's a more complete library (preferably free) available that will save some time.
Update:
If you're going with a custom solution from scratch, I've seen another example on Delphi Central that might be an even better starting point.
I will recommend you, read some links on my site. Are explained and all the source code is available; You can see and get some usefull for you.
Plugin system in Delphi - Part 2
Not directly what you need, is a plugin system for Delphi. But all the samples are based on a drawing tool that uses Shapes (Creating, selecting, resizing). You can review the code and extract what you need.
Sample manipulating of "Maps and Figures"
Sample of how to create, select and move components at runtime (in this case with TImage).
- Select shapes visually: Shows different ways to select shapes visually.
The web is in Spanish, but you can generate an authomatic translation on the web itself.
Anyway the code is commented.
Regards.
Excuse-me for my bad english.
One freeware option would be TssControlSizer. Just change the "control" property to the control you want to manipulate resize/move.
Not sure if you've moved on now with this Bruce but if you haven't, it might be worth looking at TMS Components Diagram Studio - it's certainly cheap, and looks quite powerful from the demo.
I would use Flex Graphics (commercial, $499 for one developer, with sources, $1500 for site-license, with source code). When I bought it, it was a lot less than that. So I guess, I wouldn't pay that now. It's a lightweight 'drawing/cad' package.
But as I already own it, I could import a page from the original document as an image, perhaps rendered in PNG or WMF, and then mark it up with lines, etc.
You could think of it as a light "cad" package. It has most primitive shapes, and you can easily create your own new objects or shapes in Delphi classes, that could be "smart shapes" like the ones in Visio.
http://www.flex-graphics.com/
Another commercial component set that I have heard only good things about is TRichView. They have a TRichViewEdit that looks like you could emulate a document markup environment easily with it.
Please check here:
TCAD -2d graphics component for delphi
http://www.codeidea.com
wish can help you.
What's the best way to set up help (specifically HTML Help) for a Delphi application? I can see several options, all of which has disadvantages. Specifically:
I could set HelpContext in the forms designer wherever appropriate, but then I'm stuck having to track numbers instead of symbolic constants.
I could set HelpContext programmatically. Then I can use symbolic constants, but I'd have more code to keep up with, and I couldn't easily check the text DFMs to see which forms still need help.
I could set HelpKeyword, but since that does a keyword lookup (like Application.HelpKeyword) rather than a topic jump (like Application.HelpJump), I'd have to make sure that each of my help pages has a unique, non-changing, top-level keyword; this seems like extra work. (And there are HelpKeyword-related VCL bugs like this and this.)
I could set HelpKeyword, set an Application.OnHelp handler to convert HelpKeyword requests to HelpJump requests so that I can assign help by topic ID instead of keyword lookup, and add code such as my own help viewer (based on HelpScribble's code) that fixes the VCL bugs and lets HelpJump work with anchors. By this point, though, I feel like I'm working against the VCL rather than with it.
Which approach did you choose for your app?
When I first started researching how to do this several years ago, I first got the "All About help files in Borland Delphi" tutorial from: http://www.ec-software.com/support_tutorials.html
In that document, the section "Preparing a help file for context sensitive help" (which in my version of the document starts on page 28). It describes a nice numbering scheme you can use to organize your numbers into sections, e.g. Starting with 100000 for your main form and continuing with 101000 or 110000 for each secondary form, etc.
But then I wanted to use descriptive string IDs instead of numbers for my Help topics. I started using THelpRouter, which is part of EC Software's free Help Suite at: http://www.ec-software.com/downloads_delphi.html
But then I settled on a Help tool that supported string ID's directly for topics (I use Dr. Explain: http://www.drexplain.com/) so now I simply use HelpJump, e.g.:
Application.HelpJump('UGQuickStart');
I hope that helps.
We use symbolic constants. Yes, it is a bit more work, but it pays off. Especially because some of our dialogs are dynamically built and sometimes require different help IDs.
I create the help file, which gets the help topic ID, and then go around the forms and set their HelpContext values to them. Since the level of maintenance needed is very low - the form is unlikely to change help file context unless something major happens - this works just fine.
We use Help&Manual - its a wonderful tool, outputting almost any format of stuff you could want, doc, rtf, html, pdf - all from the same source. It will even read in (or paste from rtf (eg MSWord). It uses topic ID's (strings) which I just keep a list of and I manually put each one into a form (or class) as it suits me. Sounds difficult but trust me you'll spend far longer hating the wrong authouring tool. I spent years finding it!
Brian