Firemonkey - updating visual components - delphi

We are working with Firemonkey since version 1, and still find difficulties updating components that are currently visible on the screen. There are many 'ways' to request a repaint in Firemonkey, perhaps too many:
Applying a style (ApplyStyle event) - mostly when it becomes visible on screen
Requesting ".repaint" - some components have this
Requesting ".realign" - sometime works, current versions of FMX seem to drop / hide it
Requesting ".invalidate" - some components, mostly forms, have this
Requesting ".invalidateRect" - most components have this
Calling the ApplyStyle event manually - not guaranteed to work and design-wise is incorrect...
Given the lacking documentation for the platform, is there a "well defined" way to change the visual appearance (internal values of a style) when a component is already displayed? I.e. a listboxItem that is already present and visible on screen, a TGrid cell, and so on. Would appreciate your thoughts...

I don't think there's a single unified 'correct way' to refresh the visual of components in Firemonkey.
However, as a recommendation from personal experience, I'd take the .repaint route - this method is at the TControl level, and so it precedes primitives and styled controls (which are generally made up of primitives) and so applies to all visual controls. It also doesn't require parameters, so it's a good all-round solution.
I have noted that Firemonkey has always had an issue correctly repainting controls of it's own accord. Often I'm left with a 'shadow' of the previous visual of a control/primitive, and must call .repaint manually to update it. This got noticeably worse with FM2 and FM3 (presumably due to optimizations made for mobile platforms), and so doing a manual .repaint -- especially where effects such as TGlow and moving or rotating controls/primitives are concerned, has become a standard practice for me.

Related

Can I enlarge the menu font size in Delphi 2?

Everything I've found says I can't do this with Delphi 2's TMainMenu but if somebody here has managed it somehow, I'd really like to know the trick. I found code that changes the System menu font size but none that confines the change to only the application. Anyone here know how to do this or do I have to just accept Delphi 2's tiny menu font size that appears on today's large screen monitors? (Moving the app to an upgraded Delphi is not the answer I need ;-)
The only way to achieve per application custom menu fonts is with an owner drawn menu. Delphi 2 does not support owner drawn menu items directly in the VCL properties of a TMainMenu component. This support was introduced only in Delphi 4.
You could still implement an owner drawn menu, but it would involve implementing them using standard Windows API techniques, and handling the required messages on the forms which own the menus involved. It is not especially difficult but not as straightforward as the event based implementation available in Delphi 4 and later.
You can still use a TMainMenu to define your menus but in your application you would then need to programmatically set the owner draw flag on the menu items and handle the resulting messages appropriately. Doing this, you will need to handle all aspects of drawing the menu - you cannot simply set/change the font and leave the system to draw the menu items. You may also need to provide additional handling for any keyboard shortcuts you have set up.
If this is a viable approach then information on implementing owner drawn menus at the API level can be found here.

BeginUpdate - EndUpdate causing form to go behind all open windows

I have ported a control heavy application in firemonkey which I have worked upon with DXScene for little over 2 years now. The sheer number of visual controls updating on every UI change warranted the BeginUpdate-EndUpdate methods prefixed and suffixed respectively in all UI update methods.
After porting, the firemonkey engine behaves erratically to these methods.
Sometimes the new controls get built but not updated with contents.
Sometimes they don't even show and a forced form minimize-maximize gets them shown.
And all the time the form gets behind all the other open windows.
Is it still advisable to use these or an alternative has been introduced in FMX?

TToolbar incompatible with TForm.DoubleBuffered?

I am using Delphi XE3.
When I create a new VCL project and drop a TToolbar on it, everything works fine - except when I activate Form1.DoubleBuffered.
From that moment on, drawing of the toolbar is broken - in designtime, it's either black, transparent, or parts of the IDE (statusbar, toolbar, etc.) are copied into it. It changes between these options when I click on it and when I change to source code (F12) and back.
In runtime, it's always black.
With DrawingStyle=dsGradient, everything works as expected. Switching back to dsNormal breaks it again.
Deactivating Form1.DoubleBuffered repairs it.
Any hints how to work around that issue?
In my opinion the solution is to set TForm.DoubleBuffered to False. Using a value of True causes all sorts of other problems. This property worked reasonably well before XP themes, but since their arrival, using TForm.DoubleBuffered has not been viable, in my view.
In addition to the problems you have encountered, I've come across lots of painting flaws when using the Windows Basic theme. I know that's not mainstream, but I happen to see that a lot with remote access. And there's more. When you double buffer a form you stop the theme animation from working. For example, a default button pulses to indicate that it is the default button.
If you get resize flickering without double buffering the form, use the ideas from my answer to another question. From the comments it seems that the flickering you wish to combat is in a paint box. I obviously don't know the details, but my experience and instincts say that you should be able to deal quite easily with that flickering at a local level. There surely should be no need for the global form wide double buffering.
As reported in this article, When not to use DoubleBuffered, some controls like TToolBar and TRichEdit don't work well with the DoubleBuffered property set to true.
The reason be be found in documentation, TWinControl.DoubleBuffered, where some WinControls can't draw themselves on a temporary bitmap (as happens when DoubleBuffered is true).
One workaround can be to put the TToolBar on a TPanel.

Positioning controls in Delphi 5 so they fill the form client area when the form is resized in the same sort of proportions as they did initially

I have a DBGrid above a group box with some buttons and edit fields and another group box below that again with some buttons. I cannot fins a setting for the align and/or anchors for the DBGrid and the group boxes so they fill the form without overlapping or leaving blank bits of form.
I am using Delphi 5 on XP Pro with all updates installed.
If I remember, there is no built-in way to do this. When I did this in Delphi I implemented it manually in the event handler for the form resize event. You can recalculate the new positions for each control based on the size of the form and the proportions of the layout you want. You can simplify it by breaking the form in to panels and setting most of the controls to align to one or more edges of their parent panel. That way you mostly just have to resize a few panels. If you have a complex form you still might need to reposition some individual controls.
You might also find a third-party container control out there which makes this easier. I would search for combinations of "flow", "layout", "table", "container".
We've struggled with this as well, and I agree with Charles M that there is no built-in way to do this.
If you're looking for an outside solution, the ExpressLayout control from Developer Express allows you to fine-tune the positioning of controls on Delphi forms. They advertise "Screen Resolution Independence - Automatically Resizable Interfaces - Look & Feel Standardization...", so it might be worth looking into.
I've never used that particular control, but we use a lot of other Developer Express controls in our commercial projects. The controls and support are excellent.
See: http://www.devexpress.com/Products/VCL/ExLayoutControl/
They don't have a trial version, but do have a 60-day no-questions-asked money-back guarantee.

Delphi: How to use windowless controls?

i know that windowless controls are not magic. A windowless control can have input focus (e.g. Internet Explorer). Input focus is nothing more than drawing either:
a blinking cursor
a dotted line around the perimeter
a slight blue tinge on a button
and when the user begins mashing keys, reacting appropriately. You know the keystrokes are meant for that focused control, because that's the control has focus.
In the case of my (Windows®) window, i would have to know that my windowless child control (let's pretend it's a descendant of TGraphicControl) gets the keyboard events. So during my form's OnKeyDown, OnChar, OnKeyUp, i would need to pretend they are going to my windowless child control.
Which i can do, but it is a pain.
But then the user will probably want to use Tab navigation, and i'll have to somehow intercept Delphi's normal tab control order handling, and hook in myself to say that this thing is the next (and previous) in the tab order.
Which i can do, but it is a pain.
And then there's ActiveControl, which doesn't understand anything except TWinControl's. So if Delphi ever tries to figure out who has focus, it will go insane. So i'd have to have an alternate implementation of ActiveControl.
Which i can do, but it is a pain.
In other words: is this just too much work? i'm fighting eveything that Delphi is, all so i can have a few dozen windowless controls accessible through keyboard input? The Delphi designers never contemplated using interactive windowless controls, and if i try now to work it in, i'll just stuck in the hurtlocker?
Delphi gave me the chance of aiding me willingly, but i have elected the way of pain.
Some further explanation of windowless controls is needed.
Not every control you interact with has to be a windows control. It is quite possible to have focus on, and send keyboard input to, a control that is not a Windows window.
For example, nearly every control you see in an Internet Explorer browser window is a windowless control. In the following screenshot you can see an edit control, which you can type in, and a button which (in this screenshot) has focus:
You can see the dotted focus rectangle, and the button is bluish (which on Windows indicates that it has focus).
If i were to press Spacebar while the Google Search button has focus, it would press the button. The reason this works is because Microsoft wrote an entire widget library of controls. These controls look and feel (almost) exactly like the regular common controls - they are very nearly exact clones of the Windows common controls, right down to the themes being applied.
Mozilla Firefox and Google Chrome also use a widget library of controls. They don't use Microsoft's built-in windowed controls, but instead use a library of graphical, interactive, windowless widgets.
And if you have a suitable development environment, then the windowless widgets work just like "normal" windowed controls. GTK+ is a widget library, and Glade is an IDE that lets you layout controls in that widget library.
i don't know in what development environment Firefox, Chrome, or Blender were created in, but their widgets support windowless controls.
So now onto my question.
Unless i'm mistaken, it appears to me that although Delphi supports a base TControl, (which has width, height, and can paint itself), it cannot receive keyboard focus. It seems to me that Borland never designed Delphi's VCL as a generic widget library. The only evidence i have to support this is that a Form's ActiveControl is a TWinControl:
property ActiveControl: TWinControl;
That doesn't mean that Delphi could be, or must be, limited to windowed controls. The VCL widget library could be extended to support giving focus to windowless controls.
But perhaps Delphi already supports windowless controls, and i just don't realize it? Is there already an established mechanism in Delphi to support giving focus to TControl's? But i'm a reasonably smart guy, and i'm pretty sure Delphi's VCL cannot do what other widget libraries can do.
Which then leads to another question: how much work would be be to subclass forms and such to support it? Is there someone else out there, perhaps someone on TeamB, who's much smarter than i, who has already tried it, and come to the conclusion that it's impossible?
i'm asking now, up front, if trying to add windowless control support is damn near impossible (i.e. futile) - so that i don't spend weeks on it for nothing. i'm trying to draw on the knowledge of a community of Delphi developers.
i'm asking a question.
It's futile to build windowless controls and fit them into Delphi's VCL framework.
You bring up Internet Explorer as an example. But in that case, it's entirely in charge of everything that resides on it. It has its own internal notion of what the active control is, but think about what it looks like from the outside: It's just one giant control. When you ask the OS what has focus, the single browser control has it, no matter which of the browser's subcontrols appears to have focus.
When you press Tab, it looks to the OS as though the browser has simply consumed a tab character, just like edit controls do. Edit controls move the cursor over a few spaces and add tab characters to their internal buffers; browser controls move the cursor to another region of the display.
You're thinking of doing all this on a Delphi TForm. Delphi forms already have a framework for managing the active control and handling keystrokes, and you're going to have to fight it all. If you want windowless controls, go the Internet Explorer route and build your own container control to hold them so that you can remain in charge of everything that happens inside it.
Your container can be a VCL control, but the things you put on it probably can't — they'll still be expecting to use the VCL focus- and keyboard-handling rules. Notice how you can't put ordinary Windows controls in Internet Explorer, either. Anything you put there needs to go through specific ActiveX interfaces. Maybe you'll need interfaces, too, or maybe you can just make your own set of control classes that descend from some special ancestor class you design to work with your container. Don't start with TGraphicControl; it's too entrenched in the VCL to be usable as the basis for your offshoot control library.
It will be a lot of work, but then again, so was Internet Explorer.
Yes, it is futile.
And it's not Delphi's fault, you're just fighting Windows itself.
If you need a control that behaves like a windowed control, use a windowed one.
And you're right, trying to recreate the whole API stack of windowed controls from scratch is a pain.
Yup, you pretty much have it figured out. Using windowless controls means that you lose everything Windows can do to help you. Having more than a couple on a single actual window is pain.
Most of these programs were most likely not originally developed using RAD type tools so had no choice but to re-invent the wheel. One of the largest advantages of Delphi is the deep VCL and 3rd party component support to provide the look you desire.
One technique that I have used with great success to reduce the amount of window handles used in a complex (tax preparation) form based application was to draw the text on a canvas, and moved a single TCustomEdit decendant to the position the user was editing. It was trivial to capture the TAB/Up/Down keys and move the edit to the appropriate position. The challenge we discovered was in drawing a hot rectangle around the mouse hovered field. We ended up with a grid array of TObject, where the array element would be nil (no field), a TLIst (grid contains multiple fields) or a a class that contained our field descriptor. This reduced the amount of range checks we had to perform since it was more likely that the box only contained a single field, or at most 4 fields.
fpGUI Toolkit is an example of what you want. The latest fpGUI code in the source code repository is based on a multi-windowed design. That simple means every widget/component has a window handle, but Windows or Linux does nothing with that window, other that basic notification messages (mouseenter, mouseexit, etc). fpGUI still has full control over where each component goes, if they are focusable, how they look etc. Some widgets/components in fpGUI are non-windowed components too. eg: TfpgScrollbar, TfpgMainMenu, the button in a ComboBox etc.
If you want a true non-windowed version, mean there is only one top-level window that has a window handle, all other widgets/components inside that window doesn't actually exist to the OS (they have no window handles), then fpGUI can help too. The initial design of fpGUI Toolkit was based on such a design. Again, look in the source code repository for the v0.4 branch of code. I that design, fpGUI had to handle absolutely everything, creating mouseenter/mouseleave events, translate co-ordinate systems for container components, handle (fake) component focus states etc... Yes the initial design is a LOT of work, but then you have a very portable framework which can easily be applied to other OSes too.
And yes, fpGUI is fully implemented in the Object Pascal language using the Free Pascal compiler to give me cross-platform support. Currently fpGUI runs on Windows, Linux (32 & 64-bit), Windows Mobile and Embedded Linux (ARM) devices.
I have no idea of what your problem really is, here, but I think this little history may be relevant...
We have an application which fills out a dozen forms. The user may fill out additional forms, and also change values filled out by the application it self.
Now, in our first implementation, we used windowed components for every single input field, so that the fields could receive focus and input. That turned out to be a big problem, because all this windows took a lot of resources.
We now have windowless controls for every input field. That means that all we end up with, is a combined drawing of the form and its input fields. When the user clicks inside the drawing, or uses some keystrokes to move/set focus, we create a new windowed control for the clicked field. When the user moves to the next input field, we destroy the first window, and create a new one. This way we only have one windowed control which again gave us a nice speed improvement.
Again - I have no idea of what you really want to manage. TWinControl is a TWinControl for a reason, but there may be a solution to what you want, what ever that would be...
I think fgGUI may help you out.
Do check its Wiki first.
I think you can use this framework for your application in Delphi as it is written totally in Pascal. Actually it is based on FreePascal ;)
HTH

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