C# IGraphicsContext.DrawImage方法代码示例

        private void DrawTiles(IGraphicsContext context, int tileSize, float realScrollBarHeight)
        {
            float deltaZoom = (float) (Zoom/Math.Floor(Zoom));
            int startDirtyTile = (int)Math.Floor((ContentOffset.X + context.DirtyRect.X) / ((float)tileSize * deltaZoom));
            int numberOfDirtyTilesToDraw = (int)Math.Ceiling(context.DirtyRect.Width / tileSize) + 1;
            var request = new WaveFormBitmapRequest()
            {
                StartTile = startDirtyTile,
                EndTile = startDirtyTile + numberOfDirtyTilesToDraw,
                TileSize = tileSize,
                BoundsWaveForm = Frame,
                Zoom = _zoom,
                DisplayType = _displayType
            };
            var tiles = _waveFormCacheService.GetTiles(request);

            //Console.WriteLine("WaveFormControl - #### startTile: {0} startTileX: {1} contentOffset.X: {2} contentOffset.X/tileSize: {3} numberOfTilesToFillWidth: {4} firstTileX: {5}", startTile, startTile * tileSize, ContentOffset.X, ContentOffset.X / tileSize, numberOfTilesToFillWidth, (startTile * tileSize) - ContentOffset.X);
            foreach (var tile in tiles)
            {
                float tileDeltaZoom = Zoom / tile.Zoom;
                float x = tile.ContentOffset.X * tileDeltaZoom;
                float tileWidth = tileSize * tileDeltaZoom;
                float tileHeight = (ShowScrollBar && Zoom > 1) ? Frame.Height - realScrollBarHeight : Frame.Height;
                //Console.WriteLine("WaveFormControl - Draw - tile - x: {0} tileWidth: {1} deltaZoom: {2}", x, tileWidth, deltaZoom);
                //Console.WriteLine("WaveFormControl - Draw - tile - tile.ContentOffset.X: {0} x: {1} tileWidth: {2} tile.Zoom: {3}", tile.ContentOffset.X, x, tileWidth, tile.Zoom);

                //context.DrawImage(new BasicRectangle(x - ContentOffset.X, 0, tileWidth, Frame.Height), tile.Image.ImageSize, tile.Image.Image);
                context.DrawImage(new BasicRectangle(x - ContentOffset.X, 0, tileWidth, tileHeight), tile.Image.ImageSize, tile.Image.Image);

                // Debug overlay
                //context.DrawRectangle(new BasicRectangle(x - ContentOffset.X, 0, tileWidth, Frame.Height), new BasicBrush(new BasicColor(0, 0, 255, 50)), _penCursorLine);
                //context.DrawText(string.Format("{0:0.0}", tile.Zoom), new BasicPoint(x - ContentOffset.X + 2, 4), _textColor, "Roboto", 11);
            }
        }

        private void DrawScrollBar(IGraphicsContext context, int tileSize, float realScrollBarHeight)
        {
            if (ShowScrollBar && Zoom > 1)
            {
                int startTile = 0;
                int numberOfTilesToFillWidth = (int)Math.Ceiling(Frame.Width / tileSize);// + 1; // maybe a bug here? when one of the tile is partially drawn, you need another one?
                var requestScrollBar = new WaveFormBitmapRequest()
                {
                    StartTile = startTile,
                    EndTile = numberOfTilesToFillWidth,
                    TileSize = tileSize,
                    BoundsWaveForm = new BasicRectangle(0, 0, Frame.Width, ScrollBarHeight), // Frame
                    Zoom = 1,
                    IsScrollBar = true,
                    DisplayType = _displayType
                };
                // TODO: Cache those tiles, we do not need to request them continually since these tiles are always at 100%
                var tilesScrollBar = _waveFormCacheService.GetTiles(requestScrollBar);
                foreach (var tile in tilesScrollBar)
                {
                    context.DrawImage(new BasicRectangle(tile.ContentOffset.X, Frame.Height - realScrollBarHeight, tileSize, realScrollBarHeight), tile.Image.ImageSize, tile.Image.Image);
                }

                // Draw a veil over the area that's not visible. The veil alpha gets stronger as the zoom progresses.
                byte startAlpha = 170;
                byte maxAlpha = 210;
                byte alpha = (byte)Math.Min(maxAlpha, (startAlpha + (60 * (Zoom / 10))));
                var colorVisibleArea = new BasicColor(32, 40, 46, alpha);
                float visibleAreaWidth = (1 / Zoom) * Frame.Width;
                float visibleAreaX = (1 / Zoom) * ContentOffset.X;
                var rectLeftArea = new BasicRectangle(0, Frame.Height - realScrollBarHeight, visibleAreaX, realScrollBarHeight);
                var rectRightArea = new BasicRectangle(visibleAreaX + visibleAreaWidth, Frame.Height - realScrollBarHeight, Frame.Width - visibleAreaX - visibleAreaWidth, realScrollBarHeight);
                //context.DrawRectangle(new BasicRectangle(visibleAreaX, Frame.Height - scrollBarHeight, visibleAreaWidth, scrollBarHeight), new BasicBrush(colorVisibleArea), new BasicPen());
                context.DrawRectangle(rectLeftArea, new BasicBrush(colorVisibleArea), new BasicPen());
                context.DrawRectangle(rectRightArea, new BasicBrush(colorVisibleArea), new BasicPen());
            }
        }

//.........这里部分代码省略.........
                        // Check if the album cover is already in the pile
                        bool albumCoverFound = false;
                        foreach (var arg in _workerUpdateAlbumArtPile)
                        {
                            // Match by file path
                            if (arg.AudioFile.FilePath.ToUpper() == audioFile.FilePath.ToUpper())
                            {
                                albumCoverFound = true;
                            }
                        }

                        // Add to the pile only if the album cover isn't already in it
                        if (!albumCoverFound)
                        {
                            // Add item to update album art worker pile
                            var arg = new SongGridViewBackgroundWorkerArgument();
                            arg.AudioFile = audioFile;
                            arg.LineIndex = row;
                            arg.RectAlbumArt = new BasicRectangle(0, 0, heightWithPadding, heightWithPadding);
                            _workerUpdateAlbumArtPile.Add(arg);
                        }
                    }
                    catch(Exception ex)
                    {
                        Console.WriteLine("SongGridViewControl - Failed to load cache image: {0}" , ex);
                    }
                }

                // There are at least two lines; is there an album cover to display?
                if (imageAlbumCover == null)
                {
                    // There is no album cover to display; display only text.
                    // Set string format
                    //stringFormat.Alignment = StringAlignment.Center;
                    //stringFormat.Trimming = StringTrimming.EllipsisWord;

                    sizeArtistName = context.MeasureText(audioFile.ArtistName, new BasicRectangle(0, 0, widthAvailableForText, heightWithPadding), _theme.FontNameAlbumArtTitle, _theme.FontSize + 2);
                    sizeAlbumTitle = context.MeasureText(audioFile.AlbumTitle, new BasicRectangle(0, 0, widthAvailableForText, heightWithPadding), _theme.FontNameAlbumArtSubtitle, _theme.FontSize);

                    // Display the album title at the top of the zome
                    rectArtistNameText = new BasicRectangle(_theme.Padding - HorizontalScrollBar.Value, y + _theme.Padding, widthAvailableForText, heightWithPadding);
                    rectAlbumTitleText = new BasicRectangle(_theme.Padding - HorizontalScrollBar.Value, y + _theme.Padding + sizeArtistName.Height, widthAvailableForText, heightWithPadding);
                    displayArtistNameAndAlbumTitle = true;
                    useAlbumArtOverlay = true;
                }
                else
                {
                    // There is an album cover to display with more than 2 lines.
                    // Set string format
                    //stringFormat.Alignment = StringAlignment.Near;
                    //stringFormat.Trimming = StringTrimming.EllipsisWord;

                    float widthRemainingForText = _columns[0].Width - (_theme.Padding * 3) - heightWithPadding;
                    sizeArtistName = context.MeasureText(audioFile.ArtistName, new BasicRectangle(0, 0, widthRemainingForText, heightWithPadding), _theme.FontNameAlbumArtTitle, _theme.FontSize + 2);
                    sizeAlbumTitle = context.MeasureText(audioFile.AlbumTitle, new BasicRectangle(0, 0, widthRemainingForText, heightWithPadding), _theme.FontNameAlbumArtSubtitle, _theme.FontSize);

                    // Try to center the cover art + padding + max text width
                    //float maxWidth = Math.Max(sizeArtistName.Width, sizeAlbumTitle.Width);
                    float albumCoverX = _theme.Padding - 2; // (_columns[0].Width - heightWithPadding - _theme.Padding - _theme.Padding - maxWidth) / 2;
                    float artistNameY = _theme.Padding + 1; // (albumCoverZoneHeight - sizeArtistName.Height - sizeAlbumTitle.Height) / 2;

                    // Display the album title at the top of the zome
                    rectArtistNameText = new BasicRectangle(albumCoverX + heightWithPadding + _theme.Padding - HorizontalScrollBar.Value, y + artistNameY, widthRemainingForText, heightWithPadding);
                    rectAlbumTitleText = new BasicRectangle(albumCoverX + heightWithPadding + _theme.Padding - HorizontalScrollBar.Value, y + artistNameY + sizeArtistName.Height + (_theme.Padding / 8f), widthRemainingForText, heightWithPadding);
                    rectAlbumCoverArt = new BasicRectangle(albumCoverX - HorizontalScrollBar.Value, y + _theme.Padding, heightWithPadding, heightWithPadding);
                    displayArtistNameAndAlbumTitle = widthRemainingForText > 20;
                    useAlbumArtOverlay = true;
                }

                // Display album cover
                if (imageAlbumCover != null)
                    context.DrawImage(rectAlbumCoverArt, new BasicRectangle(0, 0, imageAlbumCover.ImageSize.Width, imageAlbumCover.ImageSize.Height), imageAlbumCover.Image);
                    //context.DrawImage(rectAlbumCoverArt, new BasicRectangle(0, 0, rectAlbumCoverArt.Width, rectAlbumCoverArt.Height), imageAlbumCover.Image);

//                if (useAlbumArtOverlay)
//                {
//                    // Draw artist name and album title background
//                    var rectArtistNameBackground = new BasicRectangle(rectArtistNameText.X - (_theme.Padding / 2), rectArtistNameText.Y - (_theme.Padding / 4), sizeArtistName.Width + _theme.Padding, sizeArtistName.Height + (_theme.Padding / 2));
//                    var rectAlbumTitleBackground = new BasicRectangle(rectAlbumTitleText.X - (_theme.Padding / 2), rectAlbumTitleText.Y - (_theme.Padding / 4), sizeAlbumTitle.Width + _theme.Padding, sizeAlbumTitle.Height + (_theme.Padding / 2));
//                    var brushTextBackground = new BasicBrush(new BasicColor(0, 0, 0, 30));
//                    context.DrawRectangle(rectArtistNameBackground, brushTextBackground, penTransparent);
//                    context.DrawRectangle(rectAlbumTitleBackground, brushTextBackground, penTransparent);
//                }

                if (displayArtistNameAndAlbumTitle)
                {
                    context.DrawText(audioFile.ArtistName, rectArtistNameText, _theme.HeaderTextColor, _theme.FontNameAlbumArtTitle, _theme.FontSize + 2);
                    context.DrawText(audioFile.AlbumTitle, rectAlbumTitleText, _theme.HeaderTextColor, _theme.FontNameAlbumArtSubtitle, _theme.FontSize);
                }

                // Draw horizontal line to distinguish albums
                // Part 1: Draw line over grid
                pen = new BasicPen(new BasicBrush(new BasicColor(180, 180, 180)), 1);
                context.DrawLine(new BasicPoint(_columns[0].Width, y), new BasicPoint(Frame.Width, y), pen);

                // Part 2: Draw line over album art zone, in a lighter color
                pen = new BasicPen(new BasicBrush(new BasicColor(115, 115, 115)), 1);
                context.DrawLine(new BasicPoint(0, y), new BasicPoint(_columns[0].Width, y), pen);
            }
        }