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Added GDI extension methods for HBITMAP - IsBottomUpDIB, IsDIB and simplified ToBitmap

pull/187/head
dahall 2020-12-07 18:54:45 -07:00
parent 7ec4f19367
commit f66e5083cd
1 changed files with 37 additions and 26 deletions
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63
PInvoke/Gdi32/GdiObjExtensions.cs
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@ -1,6 +1,7 @@
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Runtime.InteropServices;
using Vanara.Extensions;
using Vanara.InteropServices;
using static Vanara.PInvoke.Gdi32;
@ -54,6 +55,26 @@ namespace Vanara.PInvoke
}
}
/// <summary>Determines whether the bitmap is a bottom-up DIB.</summary>
/// <param name="hbmp">The handle of the bitmap to assess.</param>
/// <returns><see langword="true"/> if the specified bitmap is a bottom-up DIB; otherwise, <see langword="false"/>.</returns>
public static bool IsBottomUpDIB(this in HBITMAP hbmp)
{
var dibSz = Marshal.SizeOf(typeof(DIBSECTION));
using var mem = GetObject(hbmp, dibSz);
return mem.Size == dibSz && mem.ToStructure<DIBSECTION>().dsBmih.biHeight > 0;
}
/// <summary>Determines whether the bitmap is a bottom-up DIB.</summary>
/// <param name="hbmp">The handle of the bitmap to assess.</param>
/// <returns><see langword="true"/> if the specified bitmap is a bottom-up DIB; otherwise, <see langword="false"/>.</returns>
public static bool IsDIB(this in HBITMAP hbmp)
{
var dibSz = Marshal.SizeOf(typeof(DIBSECTION));
using var mem = GetObject(hbmp, dibSz);
return mem.Size == dibSz;
}
/// <summary>Creates a <see cref="Bitmap"/> from an <see cref="HBITMAP"/> preserving transparency, if possible.</summary>
/// <param name="hbmp">The HBITMAP value.</param>
/// <returns>The Bitmap instance. If <paramref name="hbmp"/> is a <c>NULL</c> handle, <see langword="null"/> is returned.</returns>
@ -63,37 +84,27 @@ namespace Vanara.PInvoke
if (hbmp.IsNull) return null;
try
{
var dibsection = GetObject<DIBSECTION>(hbmp);
var dib = GetObject<DIBSECTION>(hbmp);
// If hbmp doesn't have ARGB, then just use Gdi+
if (dibsection.dsBm.bmBitsPixel != 32) return Image.FromHbitmap((IntPtr)hbmp);
// Create resulting bitmap of same size with transparency and lock in memory
var bitmap = new Bitmap(dibsection.dsBm.bmWidth, dibsection.dsBm.bmHeight, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
var bmpData = bitmap.LockBits(new Rectangle(Point.Empty, bitmap.Size), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
// Grab arrays to both DIB and result
using var mstr = new SafeNativeArray<RGBQUAD>(dibsection.dsBm.bmBits, (int)dibsection.dsBmih.biSizeImage, false);
using var bstr = new SafeNativeArray<RGBQUAD>(bmpData.Scan0, (int)dibsection.dsBmih.biSizeImage, false);
// Copy all semi-transparent bits
for (int i = 0; i < mstr.Count; i++)
{
var rgbquad = mstr[i];
// If pixel is 100% transparent, skip pixel
if (rgbquad.rgbReserved != 0)
bstr[i] = rgbquad;
}
bitmap.UnlockBits(bmpData);
if (dib.dsBm.bmBitsPixel != 32) throw new Exception();
// Create resulting bitmap from DIB info
var bitmap = new Bitmap(dib.dsBmih.biWidth, dib.dsBmih.biHeight, dib.dsBm.bmWidthBytes, System.Drawing.Imaging.PixelFormat.Format32bppArgb, dib.dsBm.bmBits);
// Hack to determine and fix if upside-down
//var lkBits = bitmap.LockBits(new System.Drawing.Rectangle(Point.Empty, bitmap.Size), System.Drawing.Imaging.ImageLockMode.ReadWrite, bitmap.PixelFormat);
//var stride = lkBits.Stride;
//bitmap.UnlockBits(lkBits);
//if (stride > 0)
// bitmap.RotateFlip(RotateFlipType.Rotate180FlipNone);
return bitmap;
}
catch
{
return Image.FromHbitmap((IntPtr)hbmp);
}
catch { }
return Image.FromHbitmap((IntPtr)hbmp);
}
/// <summary>Creates a <see cref="Bitmap"/> from an <see cref="SafeHBITMAP"/> preserving transparency, if possible.</summary>
/// <param name="hbmp">The SafeHBITMAP value.</param>
/// <returns>The Bitmap instance. If <paramref name="hbmp"/> is a <c>NULL</c> handle, <see langword="null"/> is returned.</returns>
public static Bitmap ToBitmap(this SafeHBITMAP hbmp) => ((HBITMAP)hbmp).ToBitmap();
#if !NET20 && !NETSTANDARD2_0 && !NETCOREAPP2_0 && !NETCOREAPP2_1
/// <summary>Creates a <see cref="System.Windows.Media.Imaging.BitmapSource"/> from an <see cref="HBITMAP"/> preserving transparency, if possible.</summary>
/// <param name="hbmp">The HBITMAP value.</param>