office-gobmx/canvas/workben/canvasdemo.cxx
Caolán McNamara f090247246 cid#1598237 Uncaught exception
Change-Id: Iab0a585048d028fda27a8b3edaad666edd0f55b3
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/167796
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>
2024-05-18 16:27:04 +02:00

675 lines
26 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
// This code strongly inspired by Miguel / Federico's Gnome Canvas demo code.
#include <sal/config.h>
#include <basegfx/polygon/b2dpolygon.hxx>
#include <basegfx/polygon/b2dpolygontools.hxx>
#include <basegfx/utils/canvastools.hxx>
#include <com/sun/star/lang/XMultiServiceFactory.hpp>
#include <com/sun/star/rendering/CompositeOperation.hpp>
#include <com/sun/star/rendering/PathCapType.hpp>
#include <com/sun/star/rendering/PathJoinType.hpp>
#include <com/sun/star/rendering/RenderState.hpp>
#include <com/sun/star/rendering/ViewState.hpp>
#include <com/sun/star/rendering/XBitmap.hpp>
#include <com/sun/star/rendering/XCanvas.hpp>
#include <com/sun/star/rendering/XGraphicDevice.hpp>
#include <com/sun/star/rendering/XSpriteCanvas.hpp>
#include <com/sun/star/uno/XComponentContext.hpp>
#include <comphelper/processfactory.hxx>
#include <comphelper/random.hxx>
#include <cppuhelper/bootstrap.hxx>
#include <o3tl/deleter.hxx>
#include <o3tl/safeint.hxx>
#include <utility>
#include <vcl/canvastools.hxx>
#include <vcl/svapp.hxx>
#include <vcl/vclmain.hxx>
#include <vcl/wrkwin.hxx>
using namespace ::com::sun::star;
static void PrintHelp()
{
fprintf( stdout, "canvasdemo - Exercise the new canvas impl\n" );
}
namespace {
class TestWindow : public WorkWindow
{
public:
TestWindow() : WorkWindow(nullptr, WB_APP | WB_STDWORK)
{
SetText(u"Canvas test"_ustr);
SetSizePixel( Size( 600, 450 ) );
EnablePaint( true );
Show();
}
virtual ~TestWindow() override {}
virtual void MouseButtonUp( const MouseEvent& /*rMEvt*/ ) override
{
//TODO: do something cool
Application::Quit();
}
virtual void Paint(vcl::RenderContext& rRenderContext, const tools::Rectangle& rRect) override;
};
class DemoRenderer
{
public:
Size maSize;
Size maBox;
rendering::ViewState maViewState;
rendering::RenderState maRenderState;
uno::Sequence< double > maColorBlack;
uno::Sequence< double > maColorRed;
uno::Reference< rendering::XCanvas > mxCanvas;
uno::Reference< rendering::XCanvasFont > mxDefaultFont;
uno::Reference< rendering::XGraphicDevice > mxDevice;
DemoRenderer( uno::Reference< rendering::XGraphicDevice > xDevice,
uno::Reference< rendering::XCanvas > xCanvas,
Size aSize ) :
maSize(aSize),
maColorBlack( vcl::unotools::colorToStdColorSpaceSequence( COL_BLACK) ),
maColorRed( vcl::unotools::colorToStdColorSpaceSequence( COL_RED) ),
mxCanvas(xCanvas),
mxDevice(std::move( xDevice ))
{
// Geometry init
geometry::AffineMatrix2D aUnit( 1,0, 0,
0,1, 0 );
maViewState.AffineTransform = aUnit;
maRenderState.AffineTransform = aUnit;
maRenderState.DeviceColor = maColorBlack;
//I can't figure out what the compositeoperation stuff does
//it doesn't seem to do anything in either VCL or cairocanvas
//I was hoping that CLEAR would clear the canvas before we paint,
//but nothing changes
maRenderState.CompositeOperation = rendering::CompositeOperation::OVER;
maBox.setWidth(aSize.Width() / 3);
maBox.setHeight(aSize.Height() / 3);
lang::Locale aLocale;
rendering::FontInfo aFontInfo;
aFontInfo.FamilyName = "Swiss";
aFontInfo.StyleName = "SansSerif";
geometry::Matrix2D aFontMatrix( 1, 0,
0, 1 );
rendering::FontRequest aFontRequest( aFontInfo, 12.0, 0.0, aLocale );
uno::Sequence< beans::PropertyValue > aExtraFontProperties;
mxDefaultFont = xCanvas->createFont( aFontRequest, aExtraFontProperties, aFontMatrix );
if( !mxDefaultFont.is() )
fprintf( stderr, "Failed to create font\n" );
}
void drawGrid()
{
tools::Long d, dIncr = maSize.Width() / 3;
for ( d = 0; d <= maSize.Width(); d += dIncr )
mxCanvas->drawLine( geometry::RealPoint2D( d, 0 ),
geometry::RealPoint2D( d, maSize.Height() ),
maViewState, maRenderState );
dIncr = maSize.Height() / 3;
for ( d = 0; d <= maSize.Height(); d += dIncr )
mxCanvas->drawLine( geometry::RealPoint2D( 0, d ),
geometry::RealPoint2D( maSize.Width(), d ),
maViewState, maRenderState );
}
void drawStringAt( OString aString, double x, double y )
{
rendering::StringContext aText;
aText.Text = OStringToOUString( aString, RTL_TEXTENCODING_UTF8 );
aText.StartPosition = 0;
aText.Length = aString.getLength();
rendering::RenderState aRenderState( maRenderState );
aRenderState.AffineTransform.m02 += x;
aRenderState.AffineTransform.m12 += y;
mxCanvas->drawText( aText, mxDefaultFont, maViewState, aRenderState, 0);
}
void drawRect( tools::Rectangle rRect, const uno::Sequence< double > &aColor, int /*nWidth*/ )
{
uno::Sequence< uno::Sequence< geometry::RealPoint2D > > aPolys
{
{
{ o3tl::narrowing<double>(rRect.Left()), o3tl::narrowing<double>(rRect.Top()) },
{ o3tl::narrowing<double>(rRect.Left()), o3tl::narrowing<double>(rRect.Bottom()) },
{ o3tl::narrowing<double>(rRect.Right()), o3tl::narrowing<double>(rRect.Bottom()) },
{ o3tl::narrowing<double>(rRect.Right()), o3tl::narrowing<double>(rRect.Top()) }
}
};
auto xPoly = mxDevice->createCompatibleLinePolyPolygon( aPolys );
xPoly->setClosed( 0, true );
rendering::RenderState aRenderState( maRenderState );
aRenderState.DeviceColor = aColor;
mxCanvas->drawPolyPolygon( xPoly, maViewState, aRenderState );
}
void translate( double x, double y)
{
maRenderState.AffineTransform.m02 += x;
maRenderState.AffineTransform.m12 += y;
}
void drawPolishDiamond( double center_x, double center_y)
{
const int VERTICES = 10;
const double RADIUS = 60.0;
int i, j;
rendering::RenderState aOldRenderState = maRenderState; // push
translate( center_x, center_y );
for (i = 0; i < VERTICES; i++)
{
double a = 2.0 * M_PI * i / VERTICES;
geometry::RealPoint2D aSrc( RADIUS * cos (a), RADIUS * sin (a) );
for (j = i + 1; j < VERTICES; j++)
{
a = 2.0 * M_PI * j / VERTICES;
// FIXME: set cap_style to 'ROUND'
mxCanvas->drawLine( aSrc,
geometry::RealPoint2D( RADIUS * cos (a),
RADIUS * sin (a) ),
maViewState, maRenderState );
}
}
maRenderState = std::move(aOldRenderState); // pop
}
void drawHilbert( double anchor_x, double anchor_y )
{
const double SCALE=7.0;
const char hilbert[] = "urdrrulurulldluuruluurdrurddldrrruluurdrurddldrddlulldrdldrrurd";
int nLength = std::size( hilbert );
uno::Sequence< geometry::RealPoint2D > aPoints( nLength );
auto pPoints = aPoints.getArray();
uno::Reference< rendering::XLinePolyPolygon2D > xPoly;
pPoints[0] = geometry::RealPoint2D( anchor_x, anchor_y );
for (int i = 0; i < nLength; i++ )
{
switch( hilbert[i] )
{
case 'u':
pPoints[i+1] = geometry::RealPoint2D( aPoints[i].X,
aPoints[i].Y - SCALE );
break;
case 'd':
pPoints[i+1] = geometry::RealPoint2D( aPoints[i].X,
aPoints[i].Y + SCALE );
break;
case 'l':
pPoints[i+1] = geometry::RealPoint2D( aPoints[i].X - SCALE,
aPoints[i].Y );
break;
case 'r':
pPoints[i+1] = geometry::RealPoint2D( aPoints[i].X + SCALE,
aPoints[i].Y );
break;
}
}
uno::Sequence< uno::Sequence< geometry::RealPoint2D > > aPolys { aPoints };
xPoly = mxDevice->createCompatibleLinePolyPolygon( aPolys );
xPoly->setClosed( 0, false );
rendering::RenderState aRenderState( maRenderState );
aRenderState.DeviceColor = maColorRed;
// aRenderState.DeviceColor[3] = 0.5;
rendering::StrokeAttributes aStrokeAttrs;
aStrokeAttrs.StrokeWidth = 4.0;
aStrokeAttrs.MiterLimit = 2.0; // ?
aStrokeAttrs.StartCapType = rendering::PathCapType::BUTT;
aStrokeAttrs.EndCapType = rendering::PathCapType::BUTT;
aStrokeAttrs.JoinType = rendering::PathJoinType::MITER;
//fprintf( stderr, "FIXME: stroking a tools::PolyPolygon doesn't show up\n" );
//yes it does
mxCanvas->strokePolyPolygon( xPoly, maViewState, aRenderState, aStrokeAttrs );
// FIXME: do this instead:
//mxCanvas->drawPolyPolygon( xPoly, maViewState, aRenderState );
}
void drawTitle( OString aTitle )
{
// FIXME: text anchoring to be done
double nStringWidth = aTitle.getLength() * 8.0;
drawStringAt ( aTitle, (maBox.Width() - nStringWidth) / 2, 15 );
}
void drawRectangles()
{
rendering::RenderState aOldRenderState = maRenderState; // push
drawTitle( "Rectangles"_ostr );
drawRect( tools::Rectangle( 20, 30, 70, 60 ), maColorRed, 8 );
// color mediumseagreen, stipple fill, outline black
drawRect( tools::Rectangle( 90, 40, 180, 100 ), maColorBlack, 4 );
// color steelblue, filled, no outline
drawRect( tools::Rectangle( 10, 80, 80, 140 ), maColorBlack, 1 );
maRenderState = std::move(aOldRenderState); // pop
}
void drawEllipses()
{
rendering::RenderState aOldRenderState = maRenderState; // push
translate( maBox.Width(), 0.0 );
drawTitle( "Ellipses"_ostr );
const basegfx::B2DPoint aCenter( maBox.Width()*.5,
maBox.Height()*.5 );
const basegfx::B2DPoint aRadii( maBox.Width()*.3,
maBox.Height()*.3 );
const basegfx::B2DPolygon& rEllipse(
basegfx::utils::createPolygonFromEllipse( aCenter,
aRadii.getX(),
aRadii.getY() ));
uno::Reference< rendering::XPolyPolygon2D > xPoly(
basegfx::unotools::xPolyPolygonFromB2DPolygon(mxDevice,
rEllipse) );
rendering::StrokeAttributes aStrokeAttrs;
aStrokeAttrs.StrokeWidth = 4.0;
aStrokeAttrs.MiterLimit = 2.0; // ?
aStrokeAttrs.StartCapType = rendering::PathCapType::BUTT;
aStrokeAttrs.EndCapType = rendering::PathCapType::BUTT;
aStrokeAttrs.JoinType = rendering::PathJoinType::MITER;
mxCanvas->strokePolyPolygon( xPoly, maViewState, maRenderState, aStrokeAttrs );
maRenderState = std::move(aOldRenderState); // pop
}
void drawText()
{
rendering::RenderState aOldRenderState = maRenderState; // push
translate( maBox.Width() * 2.0, 0.0 );
drawTitle( "Text"_ostr );
translate( 0.0,
maBox.Height() * .5 );
drawTitle( "This is lame"_ostr );
maRenderState = std::move(aOldRenderState); // pop
}
void drawImages()
{
rendering::RenderState aOldRenderState = maRenderState; // push
translate( 0.0, maBox.Height() );
drawTitle( "Images"_ostr );
uno::Reference< rendering::XBitmap > xBitmap(mxCanvas, uno::UNO_QUERY);
if( !xBitmap.is() )
return;
translate( maBox.Width()*0.1, maBox.Height()*0.2 );
maRenderState.AffineTransform.m00 *= 4.0/15;
maRenderState.AffineTransform.m11 *= 3.0/15;
mxCanvas->drawBitmap(xBitmap, maViewState, maRenderState);
// uno::Reference< rendering::XBitmap > xBitmap2( xBitmap->getScaledBitmap(geometry::RealSize2D(48, 48), false) );
// mxCanvas->drawBitmap(xBitmap2, maViewState, maRenderState); //yes, but where?
//cairo-canvas says:
//called CanvasHelper::getScaledBitmap, we return NULL, TODO
//Exception 'BitmapEx vclcanvas::tools::bitmapExFromXBitmap(const css::uno::Reference<css::rendering::XBitmap>&),
//bitmapExFromXBitmap(): could not extract BitmapEx' thrown
//vcl-canvas says:
//Exception 'BitmapEx vclcanvas::tools::bitmapExFromXBitmap(const css::uno::Reference<css::rendering::XBitmap>&),
//bitmapExFromXBitmap(): could not extract bitmap' thrown
// Thorsten says that this is a bug, and Thorsten never lies.
maRenderState = std::move(aOldRenderState); // pop
}
void drawLines()
{
rendering::RenderState aOldRenderState = maRenderState; // push
translate( maBox.Width(), maBox.Height() );
drawTitle( "Lines"_ostr );
drawPolishDiamond( 70.0, 80.0 );
drawHilbert( 140.0, 140.0 );
maRenderState = std::move(aOldRenderState); // pop
}
void drawCurves()
{
rendering::RenderState aOldRenderState = maRenderState; // push
translate( maBox.Width() * 2.0, maBox.Height() );
drawTitle( "Curves"_ostr );
translate( maBox.Width() * .5, maBox.Height() * .5 );
const double r= 30.0;
const int num_curves = 3;
//hacky hack hack
uno::Sequence< geometry::RealBezierSegment2D > aBeziers (num_curves);
auto pBeziers = aBeziers.getArray();
uno::Reference< rendering::XBezierPolyPolygon2D > xPoly;
for (int i= 0; i < num_curves; i++)
pBeziers[i]= geometry::RealBezierSegment2D( r * cos(i*2*M_PI/num_curves), //Px
r * sin(i*2*M_PI/num_curves), //py
r * 2 * cos((i*2*M_PI + 2*M_PI)/num_curves), //C1x
r * 2 * sin((i*2*M_PI + 2*M_PI)/num_curves), //C1y
r * 2 * cos((i*2*M_PI + 2*M_PI)/num_curves), //C2x
r * 2 * sin((i*2*M_PI + 2*M_PI)/num_curves)); //C2y
uno::Sequence< uno::Sequence< geometry::RealBezierSegment2D > > aPolys { aBeziers };
xPoly = mxDevice->createCompatibleBezierPolyPolygon(aPolys);
xPoly->setClosed( 0, true );
//uno::Reference< rendering::XBezierPolyPolygon2D> xPP( xPoly, uno::UNO_QUERY );
//compiles, but totally screws up. I think it is interpreting the bezier as a line
rendering::StrokeAttributes aStrokeAttrs;
aStrokeAttrs.StrokeWidth = 4.0;
aStrokeAttrs.MiterLimit = 2.0; // ?
aStrokeAttrs.StartCapType = rendering::PathCapType::BUTT;
aStrokeAttrs.EndCapType = rendering::PathCapType::BUTT;
aStrokeAttrs.JoinType = rendering::PathJoinType::MITER;
mxCanvas->strokePolyPolygon( xPoly, maViewState, maRenderState, aStrokeAttrs );
//you can't draw a BezierPolyPolygon2D with this, even though it is derived from it
//mxCanvas->drawPolyPolygon( xPoly, maViewState, maRenderState );
maRenderState = std::move(aOldRenderState); // pop
}
double gimmerand()
{
return comphelper::rng::uniform_real_distribution(0, 100);
}
void drawArcs()
{
rendering::RenderState aOldRenderState = maRenderState; // push
translate( 0.0, maBox.Height() * 2.0 );
drawTitle( "Arcs"_ostr );
//begin hacks
//This stuff doesn't belong here, but probably in curves
//This stuff doesn't work in VCL b/c vcl doesn't do beziers
//Hah! Every time the window redraws, we do this
double bx;
double by;
bx= gimmerand();
by= gimmerand();
for (int i= 0; i < 1; i++)
{
double ax;
double ay;
//point a= point b;
ax= bx;
ay= by;
//point b= rand;
bx= gimmerand();
by= gimmerand();
double c1x= gimmerand();
double c1y= gimmerand();
double c2x= gimmerand();
double c2y= gimmerand();
maRenderState.DeviceColor = maColorRed;
mxCanvas->drawLine(geometry::RealPoint2D(ax, ay), geometry::RealPoint2D(c1x, c1y), maViewState, maRenderState);
mxCanvas->drawLine(geometry::RealPoint2D(c1x, c1y), geometry::RealPoint2D(c2x, c2y), maViewState, maRenderState);
mxCanvas->drawLine(geometry::RealPoint2D(bx, by), geometry::RealPoint2D(c2x, c2y), maViewState, maRenderState);
//draw from a to b
geometry::RealBezierSegment2D aBezierSegment(
ax, //Px
ay, //Py
c1x,
c1x,
c2x,
c2y
);
geometry::RealPoint2D aEndPoint(bx, by);
maRenderState.DeviceColor = maColorBlack;
mxCanvas->drawBezier(
aBezierSegment,
aEndPoint,
maViewState, maRenderState );
}
maRenderState = std::move(aOldRenderState); // pop
}
void drawRegularPolygon(double centerx, double centery, int sides, double r)
{
//hacky hack hack
uno::Sequence< geometry::RealPoint2D > aPoints (sides);
auto pPoints = aPoints.getArray();
uno::Reference< rendering::XLinePolyPolygon2D > xPoly;
for (int i= 0; i < sides; i++)
{
pPoints[i]= geometry::RealPoint2D( centerx + r * cos(i*2 * M_PI/sides),
centery + r * sin(i*2 * M_PI/sides));
}
uno::Sequence< uno::Sequence< geometry::RealPoint2D > > aPolys { aPoints };
xPoly = mxDevice->createCompatibleLinePolyPolygon( aPolys );
xPoly->setClosed( 0, true );
rendering::RenderState aRenderState( maRenderState );
aRenderState.DeviceColor = maColorRed;
mxCanvas->drawPolyPolygon( xPoly, maViewState, aRenderState);
mxCanvas->fillPolyPolygon( xPoly,
maViewState,
aRenderState );
}
void drawPolygons()
{
rendering::RenderState aOldRenderState = maRenderState; // push
translate( maBox.Width() * 1.0, maBox.Height() * 2.0 );
drawTitle( "Polygons"_ostr );
int sides= 3;
for (int i= 1; i <= 4; i++)
{
drawRegularPolygon(35*i, 35, sides, 15);
sides++;
}
maRenderState = std::move(aOldRenderState); // pop
}
void drawWidgets() // FIXME: prolly makes no sense
{
rendering::RenderState aOldRenderState = maRenderState; // push
translate( maBox.Width() * 2.0, maBox.Height() * 2.0 );
drawTitle( "Widgets"_ostr );
maRenderState = std::move(aOldRenderState); // pop
}
};
}
void TestWindow::Paint(vcl::RenderContext&, const tools::Rectangle&)
{
try
{
uno::Reference< rendering::XCanvas > xVDevCanvas( GetOutDev()->GetCanvas(),
uno::UNO_SET_THROW );
uno::Reference< rendering::XGraphicDevice > xVDevDevice( xVDevCanvas->getDevice(),
uno::UNO_SET_THROW );
DemoRenderer aVDevRenderer( xVDevDevice, xVDevCanvas, GetSizePixel());
xVDevCanvas->clear();
aVDevRenderer.drawGrid();
aVDevRenderer.drawRectangles();
aVDevRenderer.drawEllipses();
aVDevRenderer.drawText();
aVDevRenderer.drawLines();
aVDevRenderer.drawCurves();
aVDevRenderer.drawArcs();
aVDevRenderer.drawPolygons();
uno::Reference< rendering::XCanvas > xCanvas( GetOutDev()->GetSpriteCanvas(),
uno::UNO_QUERY_THROW );
uno::Reference< rendering::XGraphicDevice > xDevice( xCanvas->getDevice(),
uno::UNO_SET_THROW );
DemoRenderer aRenderer( xDevice, xCanvas, GetSizePixel() );
xCanvas->clear();
aRenderer.drawGrid();
aRenderer.drawRectangles();
aRenderer.drawEllipses();
aRenderer.drawText();
aRenderer.drawLines();
aRenderer.drawCurves();
aRenderer.drawArcs();
aRenderer.drawPolygons();
aRenderer.drawWidgets();
aRenderer.drawImages();
// check whether virdev actually contained something
uno::Reference< rendering::XBitmap > xBitmap(xVDevCanvas, uno::UNO_QUERY);
if( !xBitmap.is() )
return;
aRenderer.maRenderState.AffineTransform.m02 += 100;
aRenderer.maRenderState.AffineTransform.m12 += 100;
xCanvas->drawBitmap(xBitmap, aRenderer.maViewState, aRenderer.maRenderState);
uno::Reference< rendering::XSpriteCanvas > xSpriteCanvas( xCanvas,
uno::UNO_QUERY );
if( xSpriteCanvas.is() )
xSpriteCanvas->updateScreen( true ); // without
// updateScreen(),
// nothing is
// visible
}
catch (const uno::Exception &e)
{
fprintf( stderr, "Exception '%s' thrown\n" ,
OUStringToOString( e.Message, RTL_TEXTENCODING_UTF8 ).getStr() );
}
}
namespace {
class DemoApp : public Application
{
public:
virtual int Main() override;
virtual void Exception(ExceptionCategory nCategory) override;
protected:
void Init() override;
void DeInit() override;
};
}
int DemoApp::Main()
{
bool bHelp = false;
for( unsigned int i = 0; i < GetCommandLineParamCount(); i++ )
{
OUString aParam = GetCommandLineParam( i );
if( aParam == "--help" || aParam == "-h" )
bHelp = true;
}
if( bHelp )
{
PrintHelp();
return 1;
}
ScopedVclPtr<TestWindow> aWindow = VclPtr<TestWindow>::Create();
suppress_fun_call_w_exception(aWindow->Show());
Application::Execute();
return 0;
}
void DemoApp::Exception( ExceptionCategory )
{
}
void DemoApp::Init()
{
try
{
uno::Reference<uno::XComponentContext> xComponentContext
= ::cppu::defaultBootstrap_InitialComponentContext();
uno::Reference<lang::XMultiServiceFactory> xMSF;
xMSF.set(xComponentContext->getServiceManager(), uno::UNO_QUERY);
if(!xMSF.is())
Application::Abort(u"Bootstrap failure - no service manager"_ustr);
::comphelper::setProcessServiceFactory(xMSF);
}
catch (const uno::Exception &e)
{
Application::Abort("Bootstrap exception " + e.Message);
}
}
void DemoApp::DeInit()
{
uno::Reference< lang::XComponent >(
comphelper::getProcessComponentContext(),
uno::UNO_QUERY_THROW)-> dispose();
::comphelper::setProcessServiceFactory(nullptr);
}
void vclmain::createApplication()
{
static DemoApp aApp;
}
// TODO
// - bouncing clip-rectangle mode - bounce a clip-rect around the window...
// - complete all of pre-existing canvas bits
// - affine transform tweakage...
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */