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// Copyright (c) 2019-2021 Jean-Philippe Bruyère <jp_bruyere@hotmail.com>
//
// This code is licensed under the MIT license (MIT) (http://opensource.org/licenses/MIT)
using System;
using System.IO;
using System.Runtime.InteropServices;
namespace Drawing2D {
public class StbImage : IDisposable {
const string stblib = "stb";
[DllImport (stblib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_load")]
static extern IntPtr Load ([MarshalAs (UnmanagedType.LPStr)] string filename, out int x, out int y, out int channels_in_file, int desired_channels);
[DllImport (stblib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_load_from_memory")]
static extern IntPtr Load (IntPtr bitmap, int byteCount, out int x, out int y, out int channels_in_file, int desired_channels);
[DllImport (stblib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "stbi_image_free")]
static extern void FreeImage (IntPtr img);
public readonly IntPtr Handle;
public readonly int Width;
public readonly int Height;
public readonly int Channels;
public int Size => Width * Height * Channels;
/// <summary>
/// Open image file with STBI library
/// </summary>
/// <param name="path">file path</param>
/// <param name="requestedChannels">Force returned channels count, set 0 for original count</param>
public StbImage (string path, int requestedChannels = 4) {
Handle = StbImage.Load (path, out Width, out Height, out Channels, requestedChannels);
if (Handle == IntPtr.Zero)
throw new Exception ($"STBI image loading error.");
if (requestedChannels > 0)
Channels = requestedChannels;
}
/// <summary>
/// Open image in memory with STBI library
/// </summary>
/// <param name="bitmap">raw bitmap datas</param>
/// <param name="bitmapByteCount">Bitmap byte count.</param>
/// <param name="requestedChannels">Force returned channels count, set 0 for original count</param>
public StbImage (IntPtr bitmap, ulong bitmapByteCount, int requestedChannels = 4) {
Handle = StbImage.Load (bitmap, (int)bitmapByteCount, out Width, out Height, out Channels, requestedChannels);
if (Handle == IntPtr.Zero)
throw new Exception ($"STBI image loading error.");
if (requestedChannels > 0)
Channels = requestedChannels;
}
public StbImage (Stream stream, int requestedChannels = 4)
{
byte [] buff = new byte [stream.Length];
stream.Read (buff, 0, (int)stream.Length);
GCHandle hnd = GCHandle.Alloc (buff, GCHandleType.Pinned);
Handle = StbImage.Load (hnd.AddrOfPinnedObject(), (int)stream.Length, out Width, out Height, out Channels, requestedChannels);
hnd.Free ();
if (Handle == IntPtr.Zero)
throw new Exception ($"STBI image loading error.");
if (requestedChannels > 0)
Channels = requestedChannels;
}
public void Dispose () {
StbImage.FreeImage (Handle);
}
}
}
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