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| -rw-r--r-- | docs/xml/fpgui_topic_embedded_forms.xml | 45 |
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diff --git a/docs/xml/fpgui_topic_embedded_forms.xml b/docs/xml/fpgui_topic_embedded_forms.xml new file mode 100644 index 00000000..4472ce4d --- /dev/null +++ b/docs/xml/fpgui_topic_embedded_forms.xml @@ -0,0 +1,45 @@ +<?xml version="1.0"?> +<fpdoc-descriptions> +<package name="fpGUI"> +<topic name="AdditionalTopics"> +<short>Additional Topics</short> +<topic name='EmbeddedForms'> + +<short>Embedded Forms as reusable Frames</short> + +<descr><p>fpGUI allows you to embed a Form inside another Form. This is similar +to the Delphi-like TFrame idea. This is very handy if you want to reuse a UI design +in multiple places in your application. +</p> +<p>At first you will be tempted to design a "frame" using a TfpgForm descendant, +because that is what the UI Designer will create for you by default. Please refrain +from using TfpgForm descendants as "frames" because there are quite a few pitfalls. +Instead, use TfpgBevel as the base class for a UI Frame design. This eliminates +all the possible problems you might get. You can still use the UI Designer because, +the UI Designer simply ignores the base class of any UI design - it only care about +what is inside the designer comment markers. +</p> +<p><b>What are the problems when you descend from TfpgForm</b></p> +<ul> +<li>Drag-n-Drop under X11 will stop working for those forms. The XDND protocol needs +to speak to the top-level form. When you use a TfpgForm as an embedded form or frame, +it will find the wrong TfpgForm, and DND will simply not work.</li> +<li>You could display an embedded form as modal, meaning it will block all other +input to the application, making the outer parent form look like it is frozen.</li> +<li>A TfpgForm has a WindowPosition property which is by default set to wpAuto. This +means, fpGUI leaves it up to the OS or Window Manager to decide where that form mast +first appear. This also means that your Top/Left position you specify for the embedded +form will most likely be ignored - giving undesired results.</li> +</ul> + +<p> +Simply using TfpgBevel (or soon to appear TfpgFrame) as your base class for embedded forms/frames +will resolve all these issues for you. For an example of this, take a look at the demo +project in [fpgui]/examples/embedded_form/ directory. +</p> +</descr> + +</topic> +</topic> +</package> +</fpdoc-descriptions> |