Exemplo n.º 1
0
        /// <summary>Service routine to paint the backing store bitmap for the map underlay.</summary>
        protected virtual Bitmap PaintBuffer(Rectangle clipBounds)
        {
            if (DataContext.Model == null)
            {
                return(null);
            }

            Bitmap bitmap = null, temp = null;

            try {
                temp = ClientSize.AllocateBitmap();
                using (var graphics = Graphics.FromImage(temp)) {
                    graphics.Clip = new Region(clipBounds);
                    graphics.Contain(PaintBuffer);
                }

                bitmap = temp;
                temp   = null;
            } finally { if (temp != null)
                        {
                            temp.Dispose();
                        }
            }

            return(bitmap);
        }
Exemplo n.º 2
0
        /// <inheritdoc/>
        protected override async void OnPaint(PaintEventArgs e)
        {
            if (e == null)
            {
                throw new ArgumentNullException(nameof(e));
            }
            if (DesignMode)
            {
                e.Graphics.FillRectangle(Brushes.Gray, ClientRectangle);  return;
            }

            if (IsMapDirty)
            {
                OnResize(EventArgs.Empty); IsMapDirty = false;
            }

            // TODO - Fix thread timing error work-around of catching and discarding InvalidOperationException.
            if (_mapBuffer != null)
            {
                try { base.OnPaint(e); } catch (InvalidOperationException) { _count++; }
            }

            var status = Interlocked.CompareExchange(ref _cacheStatus, _IS_PAINTING, _NEEDS_PAINTING);

            if (status == _NEEDS_PAINTING)
            {
                try {
                    if (_backBuffer != null)
                    {
                        _backBuffer.Dispose();
                    }

                    _backBuffer = Interlocked.Exchange(ref _mapBuffer, await PaintBufferAsync(ClientRectangle));

                    if (_backBuffer != null)
                    {
                        _backBuffer.Dispose();
                    }
                    _backBuffer = ClientSize.AllocateBitmap();
                } catch (InvalidOperationException) {
                    if (_backBuffer == null)
                    {
                        _backBuffer = ClientSize.AllocateBitmap();
                    }

                    Interlocked.CompareExchange(ref _cacheStatus, _NEEDS_PAINTING, _IS_PAINTING);
                    Thread.Sleep(250);
                } finally { Interlocked.CompareExchange(ref _cacheStatus, _IS_READY, _IS_PAINTING); }
                Refresh();
            }
            IsUnitsDirty = false;
        }