A GTK GLArea widget that renders pyramidal slide tiles directly on the GPU. Eliminates ReadPixels overhead by rendering to screen instead of copying to CPU. Supports SkiaSharp overlay for annotations via GRContext. More...

Inheritance diagram for BioGTK.SlideGLArea:

Public Member Functions
void	UploadTileTexture (TileIndex index, byte[] pixelData, int tileWidth, int tileHeight)
	Upload a tile texture to the GPU. Call from the main thread.

void	GetUploadedTileSize (TileIndex index, out int w, out int h)
	Get the uploaded texture dimensions for a cached tile. Returns (0,0) if the tile is not in the cache.

bool	HasTileTexture (TileIndex index)
	Check if a tile texture is already in the GPU cache.

void	ReleaseTileTexture (TileIndex index)
	Release a specific tile texture.

void	ReleaseLevelTextures (int level)
	Release all textures for a specific pyramid level.

void	ClearTextureCache ()
	Clear all cached textures.

void	RequestRedraw ()
	Request a redraw of the GLArea.

void	SetTilesToRender (IEnumerable< TileRenderInfo > tiles)
	Prepare tiles for rendering. Call before RequestRedraw().

byte[]	ReadPixels ()
	Read pixels from the current framebuffer (for export/save operations). This is slow - only use for export, not display.

Properties
List< TileRenderInfo >	TilesToRender = new() `[get]`

bool	NeedsRedraw = true `[get, set]`

bool	PreservePreviousFrameWhileIncomplete = false `[get, set]`

float	ImageScreenX = -1 `[get, set]`

float	ImageScreenY = -1 `[get, set]`

float	ImageScreenW = -1 `[get, set]`

float	ImageScreenH = -1 `[get, set]`

int	CachedTextureCount `[get]`

Events
Action< SKCanvas, int, int >	OnSkiaRender
	Event fired during Skia rendering phase for annotation drawing.

Detailed Description

A GTK GLArea widget that renders pyramidal slide tiles directly on the GPU. Eliminates ReadPixels overhead by rendering to screen instead of copying to CPU. Supports SkiaSharp overlay for annotations via GRContext.

Definition at line 19 of file SlideGLArea.cs.

Constructor & Destructor Documentation

◆ SlideGLArea()

BioGTK.SlideGLArea.SlideGLArea ( )

Definition at line 135 of file SlideGLArea.cs.

        {
            HasDepthBuffer = false;
            HasStencilBuffer = false;
            AutoRender = false;  // We control when to render
 
            Realized += OnRealized;
            //Unrealize += OnUnrealize;
            Render += OnRender;
            Resize += OnResized;
        }

Member Function Documentation

◆ ClearTextureCache()

void BioGTK.SlideGLArea.ClearTextureCache ( )

Clear all cached textures.

Definition at line 607 of file SlideGLArea.cs.

        {
            if (!_glInitialized) return;
 
            MakeCurrent();
 
            foreach (var tex in _textureCache.Values)
            {
                GL.DeleteTexture(tex);
            }
            _textureCache.Clear();
            _textureSizes.Clear();
            _textureBytes = 0;
        }

◆ GetUploadedTileSize()

void BioGTK.SlideGLArea.GetUploadedTileSize	(	TileIndex	index,
		out int	w,
		out int	h )

Get the uploaded texture dimensions for a cached tile. Returns (0,0) if the tile is not in the cache.

Definition at line 548 of file SlideGLArea.cs.

        {
            if (_textureSizes.TryGetValue(index, out var sz))
            { w = sz.w; h = sz.h; }
            else
            { w = 0; h = 0; }
        }

◆ HasTileTexture()

bool BioGTK.SlideGLArea.HasTileTexture ( TileIndex index )

Check if a tile texture is already in the GPU cache.

Definition at line 559 of file SlideGLArea.cs.

        {
            return _textureCache.ContainsKey(index);
        }

◆ ReadPixels()

byte[] BioGTK.SlideGLArea.ReadPixels ( )

Read pixels from the current framebuffer (for export/save operations). This is slow - only use for export, not display.

Definition at line 674 of file SlideGLArea.cs.

        {
            if (!_glInitialized) return null;
 
            MakeCurrent();
 
            int width = AllocatedWidth;
            int height = AllocatedHeight;
 
            byte[] pixels = new byte[width * height * 4];
            GL.ReadPixels(0, 0, width, height, PixelFormat.Rgba, PixelType.UnsignedByte, pixels);
 
            return pixels;
        }

◆ ReleaseLevelTextures()

void BioGTK.SlideGLArea.ReleaseLevelTextures ( int level )

Release all textures for a specific pyramid level.

Definition at line 585 of file SlideGLArea.cs.

        {
            if (!_glInitialized) return;
 
            MakeCurrent();
 
            var toRemove = _textureCache.Where(kvp => kvp.Key.Level == level).ToList();
            foreach (var kvp in toRemove)
            {
                GL.DeleteTexture(kvp.Value);
                if (_textureSizes.TryGetValue(kvp.Key, out var sz))
                {
                    _textureBytes -= (long)sz.w * sz.h * 4;
                    _textureSizes.Remove(kvp.Key);
                }
                _textureCache.Remove(kvp.Key);
            }
        }

◆ ReleaseTileTexture()

void BioGTK.SlideGLArea.ReleaseTileTexture ( TileIndex index )

Release a specific tile texture.

Definition at line 567 of file SlideGLArea.cs.

        {
            if (_textureCache.TryGetValue(index, out int tex))
            {
                MakeCurrent();
                GL.DeleteTexture(tex);
                _textureCache.Remove(index);
                if (_textureSizes.TryGetValue(index, out var sz))
                {
                    _textureBytes -= (long)sz.w * sz.h * 4;
                    _textureSizes.Remove(index);
                }
            }
        }

◆ RequestRedraw()

void BioGTK.SlideGLArea.RequestRedraw ( )

Request a redraw of the GLArea.

Definition at line 645 of file SlideGLArea.cs.

        {
            NeedsRedraw = true;
            QueueRender();
            QueueDraw();
 
            if (IsRealized && Window != null)
            {
                Window.InvalidateRect(Allocation, false);
                Window.ProcessUpdates(true);
            }
        }

◆ SetTilesToRender()

void BioGTK.SlideGLArea.SetTilesToRender ( IEnumerable< TileRenderInfo > tiles )

Prepare tiles for rendering. Call before RequestRedraw().

Definition at line 661 of file SlideGLArea.cs.

        {
            TilesToRender.Clear();
            TilesToRender.AddRange(tiles);
            LogDiag($"[SetTilesToRender] count={TilesToRender.Count}");
        }

◆ UploadTileTexture()

void BioGTK.SlideGLArea.UploadTileTexture	(	TileIndex	index,
		byte[]	pixelData,
		int	tileWidth,
		int	tileHeight )

Upload a tile texture to the GPU. Call from the main thread.

Definition at line 458 of file SlideGLArea.cs.

        {
            if (!_glInitialized)
            {
                LogDiag($"[UploadTileTexture] gl-not-initialized tile={index}");
                return;
            }
 
            if (pixelData == null || pixelData.Length == 0)
            {
                LogDiag($"[UploadTileTexture] empty pixel data tile={index}");
                return;
            }
 
            // The buffer is always BGRA = 4 bytes per pixel.
            // GetTile pads every tile — including edge tiles — to exactly
            // tileWidth x tileHeight pixels, so the dimensions passed by SlideRenderer
            // (the schema tile size) always match the buffer. We just validate and bail
            // on any genuine mismatch rather than trying to guess new dimensions.
            if (tileWidth <= 0 || tileHeight <= 0)
            {
                LogDiag($"[UploadTileTexture] invalid dimensions tile={index} size={tileWidth}x{tileHeight}");
                return;
            }
 
            int expectedBytes = tileWidth * tileHeight * 4;
            if (pixelData.Length < expectedBytes)
            {
                LogDiag($"[UploadTileTexture] buffer too small tile={index} need={expectedBytes} got={pixelData.Length}");
                return;
            }
 
            MakeCurrent();
 
            // Check if already cached
            if (_textureCache.ContainsKey(index))
            {
                LogDiag($"[UploadTileTexture] already cached tile={index}");
                return;
            }
 
            long newTextureBytes = (long)tileWidth * tileHeight * 4;
 
            // Evict old textures if the cache is full or if the new upload would
            // push the total texture budget over its byte cap.
            while (_textureCache.Count > 0 &&
                   (_textureCache.Count >= MAX_CACHED_TEXTURES ||
                    _textureBytes + newTextureBytes > MAX_CACHED_TEXTURE_BYTES))
            {
                EvictOldestTextures(1);
            }
 
            // Create and upload texture.
            // Pin the managed array explicitly so the GC cannot relocate it while the
            // driver is reading from the pointer (avoids ExecutionEngineException).
            // PixelFormat.Bgra matches the byte order produced by ReadRegionAsync.
            int tex = GL.GenTexture();
            GL.BindTexture(TextureTarget.Texture2D, tex);
            GL.PixelStore(PixelStoreParameter.UnpackAlignment, 4);
 
            var handle = System.Runtime.InteropServices.GCHandle.Alloc(pixelData, System.Runtime.InteropServices.GCHandleType.Pinned);
            try
            {
                GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba,
                              tileWidth, tileHeight, 0,
                              PixelFormat.Bgra, PixelType.UnsignedByte,
                              handle.AddrOfPinnedObject());
            }
            finally
            {
                handle.Free();
            }
 
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.ClampToEdge);
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.ClampToEdge);
 
            GL.BindTexture(TextureTarget.Texture2D, 0);
 
            _textureCache[index] = tex;
            _textureSizes[index] = (tileWidth, tileHeight);
            _textureBytes += newTextureBytes;
            LogDiag($"[UploadTileTexture] uploaded tile={index} tex={tex} size={tileWidth}x{tileHeight} bytes={pixelData.Length}");
        }

Property Documentation

◆ CachedTextureCount

int BioGTK.SlideGLArea.CachedTextureCount

get

Definition at line 668 of file SlideGLArea.cs.

◆ ImageScreenH

float BioGTK.SlideGLArea.ImageScreenH = -1

getset

Definition at line 72 of file SlideGLArea.cs.

72{ get; set; } = -1;

◆ ImageScreenW

float BioGTK.SlideGLArea.ImageScreenW = -1

getset

Definition at line 71 of file SlideGLArea.cs.

71{ get; set; } = -1;

◆ ImageScreenX

float BioGTK.SlideGLArea.ImageScreenX = -1

getset

Definition at line 69 of file SlideGLArea.cs.

69{ get; set; } = -1;

◆ ImageScreenY

float BioGTK.SlideGLArea.ImageScreenY = -1

getset

Definition at line 70 of file SlideGLArea.cs.

70{ get; set; } = -1;

◆ NeedsRedraw

bool BioGTK.SlideGLArea.NeedsRedraw = true

getset

Definition at line 63 of file SlideGLArea.cs.

63{ get; set; } = true;

◆ PreservePreviousFrameWhileIncomplete

bool BioGTK.SlideGLArea.PreservePreviousFrameWhileIncomplete = false

getset

Definition at line 64 of file SlideGLArea.cs.

64{ get; set; } = false;

◆ TilesToRender

List<TileRenderInfo> BioGTK.SlideGLArea.TilesToRender = new()

get

Definition at line 62 of file SlideGLArea.cs.

62{ get; } = new();

Event Documentation

◆ OnSkiaRender

Action<SKCanvas, int, int> BioGTK.SlideGLArea.OnSkiaRender

Event fired during Skia rendering phase for annotation drawing.

Definition at line 77 of file SlideGLArea.cs.

The documentation for this class was generated from the following file:

BioGTK/BioGTK/Source/SlideGLArea.cs

Public Member Functions

Properties

Events

Detailed Description

Constructor & Destructor Documentation

◆ SlideGLArea()

Member Function Documentation

◆ ClearTextureCache()

◆ GetUploadedTileSize()

◆ HasTileTexture()

◆ ReadPixels()

◆ ReleaseLevelTextures()

◆ ReleaseTileTexture()

◆ RequestRedraw()

◆ SetTilesToRender()

◆ UploadTileTexture()

Property Documentation

◆ CachedTextureCount

◆ ImageScreenH

◆ ImageScreenW

◆ ImageScreenX

◆ ImageScreenY

◆ NeedsRedraw

◆ PreservePreviousFrameWhileIncomplete

◆ TilesToRender

Event Documentation

◆ OnSkiaRender