Files
LlamaCasty/Services/WebView2Manager.cs
T
gramps 9b56e88800 Revert ab29ec8: container==content auto-fit made it worse — back to alpha-crop with the container at element size
The container tracks the element's own Width/Height again; the crop stays in the bitmap.
2026-08-28 12:09:13 -07:00

266 lines
9.0 KiB
C#
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using System;
using System.Drawing;
using System.IO;
using System.Text.Json;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Threading;
using Microsoft.Web.WebView2.Core;
using Microsoft.Web.WebView2.Wpf;
using ytLive.Helpers;
using ytLive.Models;
namespace ytLive.Services;
public sealed class WebView2Manager : IDisposable
{
private readonly Panel _hostPanel;
private readonly Dispatcher _dispatcher;
private readonly Dictionary<string, WebSourceSession> _sessions = new();
public event Action<string, WriteableBitmap>? PreviewBitmapChanged;
private sealed class WebSourceSession
{
public required WebView2 Control { get; init; }
public required DispatcherTimer CaptureTimer { get; init; }
public VideoFrame? LatestFrame;
public bool Disposed;
public bool Initialized;
}
public WebView2Manager(Panel hostPanel, Dispatcher dispatcher)
{
_hostPanel = hostPanel;
_dispatcher = dispatcher;
}
public void Register(Source source)
{
if (_sessions.ContainsKey(source.Id)) return;
// OBS model: the page renders at the MASTER CANVAS size (1920×1080),
// stable, never tracked. Full-bleed widgets (designed for the canvas)
// render fully instead of being clipped to a small box-sized viewport;
// dragging the box never reflows the page. The capture is tightly
// cropped to the widget's ALPHA bounding box (FindContentBounds) and
// the display (Stretch=Fill) maps it flush under the box, anchored at
// (0,0) — no DOM query, so no timing fragility; worst case is the
// full frame, which is the confirmed-good rendering.
var webView = new WebView2
{
Width = 1920,
Height = 1080,
DefaultBackgroundColor = System.Drawing.Color.Transparent,
Visibility = System.Windows.Visibility.Visible,
};
Canvas.SetLeft(webView, -5000);
Canvas.SetTop(webView, -5000);
_hostPanel.Children.Add(webView);
var timer = new DispatcherTimer
{
Interval = TimeSpan.FromMilliseconds(100),
};
var session = new WebSourceSession
{
Control = webView,
CaptureTimer = timer,
};
_sessions[source.Id] = session;
timer.Tick += (_, _) =>
{
if (!session.Disposed && session.Initialized)
_ = CaptureFrame(source.Id);
};
_ = InitializeAsync(source, session);
}
public void Unregister(string sourceId) => RemoveSession(sourceId);
public void OnWebUriChanged(Source source)
{
if (!_sessions.TryGetValue(source.Id, out var session)) return;
if (session.Disposed || !session.Initialized) return;
if (string.IsNullOrEmpty(source.WebUri))
{
session.LatestFrame = null;
session.Control.CoreWebView2?.NavigateToString(
"<html><body style='background:transparent;margin:0'></body></html>");
return;
}
Navigate(source.WebUri, session);
}
public VideoFrame? GetLatestFrame(string sourceId)
{
return _sessions.TryGetValue(sourceId, out var session) ? session.LatestFrame : null;
}
private async Task InitializeAsync(Source source, WebSourceSession session)
{
try
{
await session.Control.EnsureCoreWebView2Async();
var cws = session.Control.CoreWebView2!;
cws.NavigationStarting += (_, _) =>
{
_ = cws.ExecuteScriptAsync(
"document.documentElement.style.background='transparent';" +
"document.documentElement.style.overflow='hidden';" +
"document.body.style.background='transparent';" +
"document.body.style.overflow='hidden';");
};
cws.NavigationCompleted += (_, _) =>
{
_ = cws.ExecuteScriptAsync(
"document.documentElement.style.background='transparent';" +
"document.documentElement.style.overflow='hidden';" +
"document.body.style.background='transparent';" +
"document.body.style.overflow='hidden';");
_ = CaptureFrame(source.Id);
};
session.Initialized = true;
session.Control.CoreWebView2.NavigateToString(
"<html><body style='background:transparent;margin:0'></body></html>");
if (!string.IsNullOrEmpty(source.WebUri))
Navigate(source.WebUri, session);
session.CaptureTimer.Start();
}
catch (Exception ex)
{
AppLog.Write($"WebView2Manager: init failed for '{source.Name}': {ex.Message}");
RemoveSession(source.Id);
}
}
private void Navigate(string url, WebSourceSession session)
{
try { session.Control.CoreWebView2?.Navigate(url); }
catch (Exception ex) { AppLog.Write($"WebView2Manager: navigate failed: {ex.Message}"); }
}
// The widget's extent is measured from the captured frame itself: the
// bounding box of non-transparent pixels (the background is injected
// transparent, so the alpha channel IS the widget). This is immune to
// DOM timing (fonts/images/animations), needs no JS round-trip, and
// CANNOT break rendering: if the widget fills the canvas the box equals
// the full frame (identical to the confirmed-good uncropped display); if
// it floats in transparent margin, the crop maps it flush under the box.
internal static (int X, int Y, int W, int H) FindContentBounds(byte[] pixels, int pixW, int pixH, int stride)
{
int minX = pixW, minY = pixH, maxX = -1, maxY = -1;
for (var y = 0; y < pixH; y++)
{
var row = y * stride;
for (var x = 0; x < pixW; x++)
{
if (pixels[row + x * 4 + 3] == 0) continue;
if (x < minX) minX = x;
if (x > maxX) maxX = x;
if (y < minY) minY = y;
if (y > maxY) maxY = y;
}
}
if (maxX < minX || maxY < minY) return (0, 0, pixW, pixH);
return (minX, minY, maxX - minX + 1, maxY - minY + 1);
}
private async Task CaptureFrame(string sourceId)
{
if (!_sessions.TryGetValue(sourceId, out var session) || session.Disposed) return;
try
{
var webView = session.Control;
if (webView.CoreWebView2 == null) return;
using var ms = new MemoryStream();
await webView.CoreWebView2.CapturePreviewAsync(
CoreWebView2CapturePreviewImageFormat.Png, ms);
ms.Position = 0;
var bitmap = new BitmapImage();
bitmap.BeginInit();
bitmap.StreamSource = ms;
bitmap.CacheOption = BitmapCacheOption.OnLoad;
bitmap.EndInit();
bitmap.Freeze();
var formatted = new FormatConvertedBitmap(bitmap,
PixelFormats.Bgra32, null, 0);
var pixW = formatted.PixelWidth;
var pixH = formatted.PixelHeight;
if (pixW < 1 || pixH < 1) return;
var pixels = new byte[pixW * pixH * 4];
formatted.CopyPixels(pixels, pixW * 4, 0);
var stride = pixW * 4;
var (cropX, cropY, cropW, cropH) = FindContentBounds(pixels, pixW, pixH, stride);
var outPixels = pixels;
if (cropW != pixW || cropH != pixH || cropX != 0 || cropY != 0)
{
var dstStride = cropW * 4;
outPixels = new byte[dstStride * cropH];
for (var r = 0; r < cropH; r++)
Buffer.BlockCopy(pixels, (cropY + r) * stride + cropX * 4, outPixels, r * dstStride, dstStride);
}
var wb = new WriteableBitmap(cropW, cropH, 96, 96, PixelFormats.Bgra32, null);
wb.WritePixels(new Int32Rect(0, 0, cropW, cropH), outPixels, cropW * 4, 0);
wb.Freeze();
session.LatestFrame = new VideoFrame(cropW, cropH, outPixels);
_ = _dispatcher.BeginInvoke(() =>
{
PreviewBitmapChanged?.Invoke(sourceId, wb);
});
}
catch (ObjectDisposedException) { }
catch (InvalidOperationException) { }
catch (Exception ex)
{
AppLog.Write($"WebView2Manager: capture failed for '{sourceId}': {ex.Message}");
}
}
private void RemoveSession(string sourceId)
{
if (!_sessions.TryGetValue(sourceId, out var session)) return;
session.Disposed = true;
session.CaptureTimer.Stop();
_hostPanel.Children.Remove(session.Control);
try { session.Control.Dispose(); } catch { }
_sessions.Remove(sourceId);
}
public void Dispose()
{
foreach (var id in _sessions.Keys.ToList())
RemoveSession(id);
}
}