Picture boxes or canvas tools in Dialogs?

[Mihalcea Bogdan]

Hello!
Which part of the API Reference I need to read about picture boxes?
Is there any "canvas" like elements for Archicad?
I really need a picture container or an canvas container where I can display and interact a .PNG, or a .SVG file.
After some user input is made, the AddOn will create a query on a database(online) which will result in an image, after that i need to update that image and so on ...

Is there any possibility to actually draw on the Dialog box?

I attached a picture where I would like to have a picture box or a canvas element so you can have an ideea. .
A C# example:

[Viktor Kovacs]

It is possible with DG::UserItem. Create one in your dialog, and than use NewDisplay::UserItemUpdateNativeContext to draw on it in the UserItemUpdate event.

[Mihalcea Bogdan]

Thanks for the fast reply.
Can you point me where I can find some documentation/help on DG::UserItem?

[Viktor Kovacs · Accepted solution]

Unfortunately there is no easy example among the example add-ons, but here are the basics.

1. Define a user item in the grc:

/* [ 1] */ UserItem			  100 100  50 50	ClientEdge

2. Initialize it in the dialog constructor:

myUserItem (GetReference (), MyUserItemID)

3. Attach to event listener.

4. Implement the UserItemUpdate function.

void MyDialog::UserItemUpdate (const DG::UserItemUpdateEvent& ev)
{
	NewDisplay::UserItemUpdateNativeContext context (ev);
	// ...
	context.DrawImage (image, width, height, 0.0f, 0.0f, 0.0f, false);
	// ...
}

[Mihalcea Bogdan]

Thank you very much Viktor Kovacs! I owe you a coffee-beer-pizza, if you have a buymeacoffe account I will send you a coffee.
I was thinking about buying the Developer Support for a year. Where can I find some information about the services included in this subscription from GRAPHISOFT?

[Mihalcea Bogdan]

Viktor wrote:
Unfortunately there is no easy example among the example add-ons, but here are the basics.

void MyDialog::UserItemUpdate (const DG::UserItemUpdateEvent& ev)
{
	NewDisplay::UserItemUpdateNativeContext context (ev);
	// ...
	context.DrawImage (image, width, height, 0.0f, 0.0f, 0.0f, false);
	// ...
}

If someone arrives to this post and does not know where the UserItemUpdateNativeContext is located it is here: AC_DEV_KIT_PATH\Support\Modules\DGGraphix

[Akos Somorjai]

Mihalcea wrote:
I was thinking about buying the Developer Support for a year. Where can I find some information about the services included in this subscription from GRAPHISOFT?

Hi Michalcea,

The subscription includes a "priority lane" via the official support channel https://graphisoft.atlassian.net/servicedesk/customer/portal/5, meaning that we guarantee a short, 72 hour feedback to your questions.

Best, Akos

[Mihalcea Bogdan]

Thank you!
I will think about this service!

[Mihalcea Bogdan]

Viktor wrote:

void MyDialog::UserItemUpdate (const DG::UserItemUpdateEvent& ev)
{
	NewDisplay::UserItemUpdateNativeContext context (ev);
	// ...
	context.DrawImage (image, width, height, 0.0f, 0.0f, 0.0f, false);
	// ...
}

This code works only inside the "UserItemUpdate" function when the UserItem updates. I am having a real hard time figuring out how to pass this context to a function like

virtual void UserItemClicked(const DGUserItemClickEvent &ev)
{
	//draw something when user clicks
}
virtual void SpecDragStarting(const ItemDragSourceEvent &ev)
{
	//do something when user starts dragging like fetch an image from Google Earth based on the new coordinates
}

I tried to reference it, but obviously I get Memory Access Exception.

[Viktor Kovacs]

It's a general rule for all applications that they should draw only when the operating system requests them to do so. In your case it means that you can draw only in the UserItemUpdate function, so the context can't be reused. Fortunately, you can request the operating system to redraw. Call the userItem.Redraw (true, true) function which will force the call of UserItemUpdate.

[Mihalcea Bogdan]

Viktor wrote:
It's a general rule for all applications that they should draw only when the operating system requests them to do so. In your case it means that you can draw only in the UserItemUpdate function, so the context can't be reused. Fortunately, you can request the operating system to redraw. Call the userItem.Redraw (true, true) function which will force the call of UserItemUpdate.

I did observe this behaviour, I thought that this kind of approach is wrong(I have some JavaScript webgl background where the context is a variable accessible by any function). Thank you again!