Re: [Wxart2d-users_dev] Drawing to a canvas
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Re: [Wxart2d-users_dev] Drawing to a canvas
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From: Mike G. <mik...@da...> - 2016-12-07 22:59:50
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Hi Klaas,
I followed your suggestion and created a class: MyDrawingPart : public
a2dDrawingPart.
I redefined a2dDrawingPart::UpdateArea with my own
MyDrawingPart::UpdateArea. I then copied the code for that function
verbatim out of drawer.cpp.
I created an a2dSmrtPtr<MyDrawingPart> m_DrawingPart, and created a new one.
I then assigned the drawing part to my a2dCanvas:
CieDiagram->SetDrawingPart(m_DrawingPart).
Now whenever I pull up the canvas, it is always blank. It never displays
the image or anything.
If I comment out the assignment
(CieDiagram->SetDrawingPart(m_DrawingPart)), and use the a2dCanvas'
default drawing part, everything works fine. Is there another step I
need to perform?
- Mike
On 12/6/2016 1:10 PM, klaas.holwerda wrote:
>
> Hi,
>
> You mixing two different concepts.
>
> One is direct drawing to a canvas using a drawing context. See
> artbase_directdraw example.
>
> The other is filling a a2dDrawing with objects, and have
> a2dDrawingPart display this on a a2dCanvas.
>
> Every change to the object in the drawing are automatically redrawn on
> the canvas in idle time.
>
> See the canvas_simple example.
>
> If you want to combine direct drawing and drawing based drawing
> objects, as you do, you need to derive from a2dDrawingPart.
>
> And redefine:
>
> virtualvoidUpdateArea( intx, inty, intwidth, intheight, wxUint8 id = 0 );
>
> In here:
>
> voida2dDrawingPart::UpdateArea( intx, inty, intwidth, intheight,
> wxUint8 id )
>
> there you see for instance PaintGrid( x, y, width, height ).
>
> But in your own version you can add extra stuff, to draw what you want
> besides what is already coming from the drawing.
>
> The drawing itself is drawn with the call to RenderTopObject(
> m_documentDrawStyle, id ) there.
>
> So to draw on top of your image, do add you stuff after that.
>
> This way you can combine static drawing (your points), with dynamic
> editable drawing objects.
>
> (If for some reason you also want to be able to edit your point, the
> story is different.)
>
> For speed have a look in the canvas_simple example at
> menu->DemoScreen->doc7
>
> If you change voidMyFrame::FillDoc7( a2dCanvasObject* root )
>
> to have the quantity and type of objects you expect, is it fast
> enough? Zoomin/out with the mouse wheel.
>
> VERY important, to test speed, you need to work with the release
> version of art2d and you app, and test outside of VCstudio.
>
> Debug version is always much slower, and inside VC, the release
> version is also slow.
>
> If after this experiment, you still think it is slow. You are against
> the limits of what wxDC drawing can do for you.
>
> For that problem I recently started to develop a OpenGl drawing
> context, which works but is also still in its youth.
>
> Both samples mentioned above can be used to test that.
>
> You need to enable wxART2D_USE_OPENGL in cmake.
>
> And search these lines to enable it.
>
> #ifwxUSE_GLCANVAS && wxART2D_USE_OPENGL
>
> #define with_GLCANVASdraw 1
>
> #endif
>
> #ifwxUSE_GLCANVAS && wxART2D_USE_OPENGL
>
> #definewith_GLCANVAS 1
>
> #endif
>
> This gives you speed you can not even dream of with plain wxWidgets
> based wxDc drawing functions.
>
> Regards,
>
> Klaas
>
>
>
> On 12/05/2016 11:59 PM, Mike Gibson wrote:
>>
>> Hello,
>>
>> I'm attempting to draw to an a2dCanvas, and am having some
>> difficulty. Usually when I draw something simple like a line on a
>> canvas, I just add an a2dSLine. However, I'm going to be adding
>> hundreds, if not thousands of points to a canvas, and using an
>> a2dSLine slows the software down tremendously.
>>
>> I assume that the software would perform faster if I were to actually
>> just draw lines on the canvas, but I'm having problems getting that
>> functionality to work.
>>
>>
>> I have an a2dCanvas in a wxDialog, and the a2dCanvas is called
>> CieDiagram. Here is what code I'm using to attempt to draw to the
>> CieDiagram:
>>
>> int TDlgCieDiagram::Execute(double x, double y, double Radius,
>> TCieVect *Points)
>> {
>> m_Drawing = new a2dDrawing();
>> CieDiagram->SetDrawing(m_Drawing);
>>
>> CieDiagram->GetDrawingPart()->SetDrawer2D( new a2dMemDcDrawer(
>> CieDiagram->GetSize() ) );
>> CieDiagram->GetDrawer2D()->SetDisplay(CieDiagram);
>> CieDiagram->GetDrawer2D()->Init();
>> CieDiagram->GetDrawer2D()->SetMappingWidthHeight(-.05, -.05, .8, .9);
>>
>> CieDiagram->GetDrawingPart()->Update( a2dCANVIEW_UPDATE_ALL );
>>
>> InitCanvas();
>>
>> AddPoints(Points);
>>
>> return ShowModal();
>> }
>>
>>
>> void TDlgCieDiagram::AddPoints(TCieVect *Points)
>> {
>> TCieVectIter Iter;
>>
>> if (Points == NULL)
>> return;
>>
>> CieDiagram->GetDrawer2D()->BeginDraw();
>>
>> CieDiagram->GetDrawer2D()->PushIdentityTransform();
>>
>> CieDiagram->GetDrawer2D()->SetDrawStyle(a2dFILLED);
>> CieDiagram->GetDrawer2D()->SetDrawerFill( a2dFill( wxColour( 12,
>> 134, 228 ), a2dFILL_SOLID ) );
>> CieDiagram->GetDrawer2D()->SetDrawerStroke(a2dStroke(
>> wxColour(0,0,0), a2dSTROKE_NORMAL));
>>
>> CieDiagram->GetDrawer2D()->SetDisableDrawing(false);
>>
>>
>> for (Iter = Points->begin(); Iter != Points->end(); ++Iter)
>> {
>> CieDiagram->GetDrawer2D()->DrawLine(Iter->x - TICK_LENGTH/4,
>> Iter->y,
>> Iter->x + TICK_LENGTH/2, Iter->y);
>> }
>>
>> CieDiagram->GetDrawer2D()->PopTransform();
>> CieDiagram->GetDrawer2D()->EndDraw();
>> }
>>
>> void TDlgCieDiagram::InitCanvas(void)
>> {
>> a2dSmrtPtr<a2dImage> Img;
>> wxFileName ExeFileName;
>>
>> // Unfix scroll max so mapping changes will work correctly. We'll
>> fix it
>> // again later.
>> CieDiagram->FixScrollMaximum( false );
>>
>> // Set Y axis positive up.
>> CieDiagram->SetYaxis( true );
>>
>> // Don't show the origin.
>> CieDiagram->SetShowOrigin( false );
>>
>> CieDiagram->SetMappingWidthHeight( -.05, -.05, .8, .9, true );
>>
>> // Define the number of world units moved when scroll.
>> CieDiagram->SetScrollStepX( 0.001 );
>> CieDiagram->SetScrollStepY( 0.001 );
>>
>> // Don't allow scrolling outside the scroll maximum.
>> CieDiagram->FixScrollMaximum( true );
>>
>>
>> Img = new a2dImage();
>> Img->SetFill( *a2dTRANSPARENT_FILL );
>> Img->SetStroke( *a2dTRANSPARENT_STROKE );
>>
>> Img->SetWidth( 0.8 );
>> Img->SetHeight( 0.9 );
>>
>> // This, annoying, wants you to set the middle position of the image.
>> // Why?! Of course it isn't documented, so it was fun figuring
>> that out.
>> Img->SetPosXY( 0.8/2, 0.9/2 );
>>
>>
>> CieDiagram->GetDrawing()->Append( Img );
>>
>>
>> ExeFileName = wxStandardPaths::Get().GetExecutablePath();
>>
>> Img->GetImage().LoadFile( ExeFileName.GetPath() +
>> _T("\\art\\cie\\") + _T("cie_532_598.bmp") );
>>
>> Img->SetDraggable(false);
>> Img->SetEditable(false);
>>
>> return;
>> }
>>
>>
>> No points ever appear on the canvas. I have attempted using the
>> Identity transform, as well as the standard tranform. I have also
>> tried adding points programmatically, and can never get any lines to
>> appear. What am I missing?
>>
>>
>> Thanks,
>> - Mike
>>
>>
>>
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>
>
>
>
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> Access to Intel Xeon Phi processor-based developer platforms.
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> Training and support from Colfax.
> Order your platform today.http://sdm.link/xeonphi
>
>
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