I am using the Teechart component that comes with Delphi XE3.
I need to have multiple graphs and then save them out to a jpg file.
The user can select a keyword and that displays each graph.
What I need to do is for each keyword, draw the graph and then
save it out to a file, without user interaction.
I have tried the event OnAfterDraw and then save the chart as an
image and then call for another keyword. However this does not work
because when you save the image it recalls the OnAfterDraw and I
either end up an endless loop OR if I set the event to nil and then
reset it back, it never gets called again.
Does anyone have any suggestions on how to do this please ?
Regards
Anthoni
You could try calling TChart.Draw(); the chart to force the chart being rendered before exporting so that you don't have the need to use the OnAfterDraw event.
OK, So I've found a way but it seems very kludgy to me.
Basically, I placed a Timer on the form and moved the teechart OnAfterDraw event to the private section. Then I build my keyword list and then start the timer.
The timer, first disables itself then adds the OnAfterDraw event to the TeeChart before calling a procedure to fill in the chart information.
Inside OnAfterDraw I save out the chart as an image, check if any more keywords are available and if so, reactivate the timer, otherwise fire my own event.
Like I said, this works but not sure of the overall ramifications of it.
If anyone has any suggestions or comments on this method I would greatly aprpeciate it.
Regards
Anthoni
Related
I have implemented a Scroll box that dynamically adds TCharts dependent on the number of channels available on an input device. The charts repaint on a loop to show the value of the voltage through the channel, so that the display outputs effectively a "real-time" view of the voltages being applied to each channel.
Currently I have an Application.ProcessMessages function to prevent the application becoming unresponsive during a run, but I would like to be able to scroll through the box whilst the channels are being displayed, without disturbing the display, which currently pauses whilst the scroll bar is clicked.
Is this possible?
Yes, this is possible.
The charts repaint on a loop ...
Repaints driven by an own loop indeed ensures respiratory distres on the system, which exactly is the reason for the need of Application.ProcessMessages. Try not to use it. Instead, you should just ask the charts to repaint themselves with Invalidate when new data comes in, and let the system decide when it is convenient to do so.
I am writing my first component for Firemonkey. It is very dynamic control and to keep refresh times minimal, when a property changes, I only want to modify the effected attributes rather than repaint the entire control.
The first issue I found was that unless you are in the Paint loop, you need to call Canvas.SetMatrix(AbsoluteMatrix) first otherwise canvas functions are referenced to the parents coordinates. I don't quite understand this.
The second issued is that when use this control on OSX, unless I call the inherited paint procedure (which I override) nothing changes on the canvas gets displayed. This works fine in Win32
Component is based off of TControl
You might not like this, but you're not supposed to paint outside of a paint event. So don't do it. Windows is a bit more forgiving if you break that rule, but you shouldn't do it on Windows either. For example, if your window is (partly) hidden, no updates are needed and the OS will skip the paint event. So instead of trying to work against the OS it is better to work with it. And usually there is a better alternative.
You can keep an internal "cache" bitmap and update that as needed. Then when the paint event comes, you can draw this entire bitmap. If possible, update this cached bitmap in the paint event if it needs changing.
If you want to temporarily highlight items, you can have a transparent window on top and paint on that window. Let the OS window manager do the heavy work for you.
Developing Smart Devices in Genexus. I am using the Load Event to load some hundreds of records (returned by a 3rd party webService) into the Grid (some rows might have different layouts).
When the user hits the search button, a ProgressIndicator is immediately shown (during the procedure execution). When the procedure ends (data retrieved), the ProgressIndicator disappears but it may take an additional 4-5 seconds for the Grid to show the fresh data.
This causes the user to think that there was a problem with the search. Then, unexpectedly, the grid refreshes.
Is it possible to, somehow, show a ProgressIndication during the Load or Refresh Events?
Or do you have any suggestions to prevent this behavior?
The main issue is that Refresh and Load events are "server" events in SD architecture so you don't have access to the device's APIs or resources like the Progress Indicator.
We had the same requirement in iOS and what we did was using the GXRefresh event.
Event 'gxrefresh'
Composite
//Your code. Example: ProgressIndicator.Hide()
EndComposite
EndEvent
Gxrefresh is a Local event that is executed after the Refresh and Load. Is a hidden event that helped us accomplish this. (This is not an official event and it can be taken out in any version of GeneXus)
So the solution is:
Start a Progress Indicator on the ClientStart event of that Panel.
Hide the Progress Indicator on the 'gxrefresh' event of that panel.
Note: Remember that in order to use the gxrefresh event you will need to add a hidden button named 'gxrefresh'. You can hide that button as you will not need it in the UI (we put it Visible=false on the application bar).
If that solution for any reason is not possible (for example the gxrefresh event is deprecated or you are developing for Android) I can think of a second WA that is not elegant at all but should work.
Start the Progress Indicator in the Client Start Event of the panel
Put a hidden variable with control type SD Chronometer.
Set the timer for 6 seconds
Stop the Progress Indicator on the Tick event of the SD Chronometer and stop the Chronometer so the Tick event is not executed any more.
These are the two options I can think of.
Maybe there is an easier way but I haven't heard of it. A Grid.DidLoad event would be great for this scenario. For sure we will have this soon or some other solution for this problem.
Links:
SD Chronometer: http://wiki.genexus.com/commwiki/servlet/hwikibypageid?25058
SD Events: http://wiki.genexus.com/commwiki/servlet/hwikibypageid?17042
Server Side Events: http://wiki.genexus.com/commwiki/servlet/hwikibypageid?24234
The way Delphi by default updates the selection with a timer can sometimes look funny if people scroll very fast (losing track), so I would like to disable that.
However, what I would like instead is that it would update selection immediately on the OnItemClick event. (i.e. I would like to force update the selection immediately before hen doing the rest of processing in the click event - that would be quite excellent.) However, after having tried quite a few things, this appears quite a bit more cumbersome to achieve than first expected.
I have tried force update selection, force animations, force updateselection etc. but none update the selection because of internal properties. Has anyone sucessfully done with without making changes to the listbox code directly?
I like the idea of the Delphi Code Insight window (custom listbox on form without borders basically) where you can click outside of the form and it will close it automatically.
My first thought was to call SetCapture/ReleaseCapture in the FormCreate and FormDestroy respectively. I set the form's caption to X/Y on the FormMouseMove, but it doesn't update the coordinates outside of the form.
If I call SetCapture/ReleaseCapture from within MouseDown and MouseUp, it does update the coordinates as expected, so that proves the concept does work.
I tried other things as well, e.g. post a WM_USER in the OnShow event, and call SetCapture from there, but it still doesn't update the coordinates. I then tried the TApplicationEvents component (OnMessage), but that doesn't work either.
I've read several articles already, but wasn't able to find what I was looking for. Some articles called SetCapture from within the MouseMove, but that doesn't work when the mouse cursor starts outside of the form. Hrm...
The next step would be to use a WindowsHook, but that's where I stopped. I know how to implement one, but it just seems like I'm missing something really obvious here. There must be a simpler way to do this.
Any ideas? :)
Cheers,
Jarno
What you want can be done easier by adding TApplicationEvents to your form and use the event OnDeactivate. That one gets triggered whenever the application loses focus.
Maybe WM_NCHITTEST can help you somehow. As they say, if the mouse is captured, this message is sent to the window that has captured the mouse. So I would capture the mouse for the form and then wait until result of this message is HTNOWHERE, which should mean "out of the window".
But as far as I can remember, this never worked for me fine, so I finally used (as you mentioned) mouse hook.But in my case I've had a lot of components on that popup form and you need to consider messaging for them too.
The implementation I've used (with a little changes) and which works is here.
I had a similar problem (I needed to implement a scrolling windows if the mouse pointer hovered over a special area and I was not able to use SetCapture)
and circumvented it using a timer + GetCursorPos method.
Just do then a ScreenToClient and check if the mouse is within the window.