GDALAdjustContrast.cs

Revision 14383, 12.5 kB (checked in by tamas, 7 months ago)
Added the GDALAdjustContrast sample to demonstrate the image correction at the C# side.
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`

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1	/******************************************************************************
2	* $Id$
3	*
4	* Name: GDALAdjustContrast.cs
5	* Project: GDAL CSharp Interface
6	* Purpose: A sample app to demonstrate how to read the dataset into the
7	* memory, adjust the contrast of the image and write back to the
8	* dataset persistently.
9	* Author: Tamas Szekeres, szekerest@gmail.com
10	*
11	******************************************************************************
12	* Copyright (c) 2007, Tamas Szekeres
13	*
14	* Permission is hereby granted, free of charge, to any person obtaining a
15	* copy of this software and associated documentation files (the "Software"),
16	* to deal in the Software without restriction, including without limitation
17	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
18	* and/or sell copies of the Software, and to permit persons to whom the
19	* Software is furnished to do so, subject to the following conditions:
20	*
21	* The above copyright notice and this permission notice shall be included
22	* in all copies or substantial portions of the Software.
23	*
24	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
25	* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
26	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
27	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
28	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
29	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
30	* DEALINGS IN THE SOFTWARE.
31	*****************************************************************************/
32
33	using System;
34	using System.Drawing;
35	using System.Drawing.Imaging;
36	using System.Drawing.Drawing2D;
37	using OSGeo.GDAL;
38
39	/**
40	* <p>Title: GDAL C# GDALAdjustContrast example.</p>
41	* <p>Description: A sample app to demonstrate how to read the dataset into the
42	* memory, adjust the contrast of the image and write back to the dataset persistently.</p>
43	* @author Tamas Szekeres (szekerest@gmail.com)
44	* @version 1.0
45	*/
46
47
48
49	/// <summary>
50	/// A sample app to demonstrate how to read the dataset into the
51	/// memory, adjust the contrast of the image and write back to the dataset persistently.
52	/// </summary>
53
54	class GDALAdjustContrast {
55
56	public static void usage()
57
58	{
59	Console.WriteLine("usage: GDALAdjustContrast {dataset name} {contrast ratio}");
60	System.Environment.Exit(-1);
61	}
62
63
64	// bitmap parameters
65	static int[] bandMap;
66	static ColorTable ct;
67	static int channelCount;
68	static bool hasAlpha;
69	static bool isPremultiplied;
70	static bool isIndexed;
71	static int channelSize;
72	static PixelFormat pixelFormat;
73	static DataType dataType;
74	static int pixelSpace;
75
76	public static void Main(string[] args)
77	{
78
79	if (args.Length != 2) usage();
80
81	// Using early initialization of System.Console
82	Console.WriteLine("Adjusting the image: " + args[0]);
83
84	try
85	{
86	float contrastRatio = float.Parse(args[1]);
87	/* -------------------------------------------------------------------- */
88	/* Register driver(s). */
89	/* -------------------------------------------------------------------- */
90	Gdal.AllRegister();
91
92	/* -------------------------------------------------------------------- */
93	/* Open dataset. */
94	/* -------------------------------------------------------------------- */
95	Dataset ds = Gdal.Open(args[0], Access.GA_Update);
96
97	if (ds == null)
98	{
99	Console.WriteLine("Can't open " + args[0]);
100	System.Environment.Exit(-1);
101	}
102
103	Bitmap bmp = CreateCompatibleBitmap(ds, ds.RasterXSize, ds.RasterYSize);
104	LoadBitmapDirect(ds, bmp, 0, 0, ds.RasterXSize, ds.RasterYSize, ds.RasterXSize, ds.RasterYSize, 0);
105	Bitmap newBitmap = (Bitmap)bmp.Clone();
106
107	//create the ColorMatrix
108	float[][] colormatrix = new float[][]
109	{
110	new float[] {contrastRatio, 0, 0, 0, 0},
111	new float[] {0, contrastRatio, 0, 0, 0},
112	new float[] {0, 0, contrastRatio, 0, 0},
113	new float[] {0, 0, 0, 1, 0},
114	new float[] {0, 0, 0, 0, 1}
115	};
116	ColorMatrix colorMatrix = new ColorMatrix(colormatrix);
117
118	//create the image attributes
119	ImageAttributes attributes = new ImageAttributes();
120
121	//set the color matrix attribute
122	attributes.SetColorMatrix(colorMatrix);
123
124	//get a graphics object from the new image
125	Graphics g = Graphics.FromImage(newBitmap);
126	//draw the original image on the new image
127	g.DrawImage(bmp,
128	new Rectangle(0, 0, bmp.Width, bmp.Height),
129	0, 0, bmp.Width, bmp.Height,
130	GraphicsUnit.Pixel, attributes);
131
132	SaveBitmapDirect(ds, newBitmap, 0, 0, ds.RasterXSize, ds.RasterYSize, ds.RasterXSize, ds.RasterYSize);
133
134	ds.FlushCache();
135
136	}
137	catch (Exception e)
138	{
139	Console.WriteLine("Application error: " + e.Message);
140	}
141	}
142
143	private static Bitmap CreateCompatibleBitmap(Dataset ds, int imageWidth, int imageHeight)
144	{
145	if (ds.RasterCount == 0)
146	return null;
147
148	bandMap = new int[4] { 1, 1, 1, 1 };
149	channelCount = 1;
150	hasAlpha = false;
151	isPremultiplied = false;
152	isIndexed = false;
153	channelSize = 8;
154	// Evaluate the bands and find out a proper image transfer format
155	for (int i = 0; i < ds.RasterCount; i++)
156	{
157	Band band = ds.GetRasterBand(i + 1);
158	if (Gdal.GetDataTypeSize(band.DataType) > 8)
159	channelSize = 16;
160
161	// retrieving the premultiplied alpha flag
162	string[] metadata = band.GetMetadata("");
163	for (int iMeta = 0; iMeta < metadata.Length; iMeta++)
164	{
165	if (metadata[iMeta].StartsWith("PREMULTIPLIED_ALPHA"))
166	isPremultiplied = true;
167	}
168
169	switch (band.GetRasterColorInterpretation())
170	{
171	case ColorInterp.GCI_AlphaBand:
172	channelCount = 4;
173	hasAlpha = true;
174	bandMap[3] = i + 1;
175	break;
176	case ColorInterp.GCI_BlueBand:
177	if (channelCount < 3)
178	channelCount = 3;
179	bandMap[0] = i + 1;
180	break;
181	case ColorInterp.GCI_RedBand:
182	if (channelCount < 3)
183	channelCount = 3;
184	bandMap[2] = i + 1;
185	break;
186	case ColorInterp.GCI_GreenBand:
187	if (channelCount < 3)
188	channelCount = 3;
189	bandMap[1] = i + 1;
190	break;
191	case ColorInterp.GCI_PaletteIndex:
192	ct = band.GetRasterColorTable();
193	isIndexed = true;
194	bandMap[0] = i + 1;
195	break;
196	case ColorInterp.GCI_GrayIndex:
197	isIndexed = true;
198	bandMap[0] = i + 1;
199	break;
200	default:
201	// we create the bandmap using the dataset ordering by default
202	if (i < 4 && bandMap[i] == 0)
203	{
204	if (channelCount < i)
205	channelCount = i;
206	bandMap[i] = i + 1;
207	}
208	break;
209	}
210	}
211
212	// find out the pixel format based on the gathered information
213	if (isIndexed)
214	{
215	pixelFormat = PixelFormat.Format8bppIndexed;
216	dataType = DataType.GDT_Byte;
217	pixelSpace = 1;
218	}
219	else
220	{
221	if (channelCount == 1)
222	{
223	if (channelSize > 8)
224	{
225	pixelFormat = PixelFormat.Format16bppGrayScale;
226	dataType = DataType.GDT_Int16;
227	pixelSpace = 2;
228	}
229	else
230	{
231	pixelFormat = PixelFormat.Format24bppRgb;
232	channelCount = 3;
233	dataType = DataType.GDT_Byte;
234	pixelSpace = 3;
235	}
236	}
237	else
238	{
239	if (hasAlpha)
240	{
241	if (channelSize > 8)
242	{
243	if (isPremultiplied)
244	pixelFormat = PixelFormat.Format64bppArgb;
245	else
246	pixelFormat = PixelFormat.Format64bppPArgb;
247	dataType = DataType.GDT_UInt16;
248	pixelSpace = 8;
249	}
250	else
251	{
252	if (isPremultiplied)
253	pixelFormat = PixelFormat.Format32bppPArgb;
254	else
255	pixelFormat = PixelFormat.Format32bppArgb;
256	dataType = DataType.GDT_Byte;
257	pixelSpace = 4;
258	}
259	channelCount = 4;
260	}
261	else
262	{
263	if (channelSize > 8)
264	{
265	pixelFormat = PixelFormat.Format48bppRgb;
266	dataType = DataType.GDT_UInt16;
267	pixelSpace = 6;
268	}
269	else
270	{
271	pixelFormat = PixelFormat.Format24bppRgb;
272	dataType = DataType.GDT_Byte;
273	pixelSpace = 3;
274	}
275	channelCount = 3;
276	}
277	}
278	}
279
280
281	// Create a Bitmap to store the GDAL image in
282	return new Bitmap(imageWidth, imageHeight, pixelFormat);
283	}
284
285	private static void LoadBitmapDirect(Dataset ds, Bitmap bitmap, int xOff, int yOff, int width, int height, int imageWidth, int imageHeight, int iOverview)
286	{
287	if (isIndexed)
288	{
289	// setting up the color table
290	if (ct != null)
291	{
292	int iCol = ct.GetCount();
293	ColorPalette pal = bitmap.Palette;
294	for (int i = 0; i < iCol; i++)
295	{
296	ColorEntry ce = ct.GetColorEntry(i);
297	pal.Entries[i] = Color.FromArgb(ce.c4, ce.c1, ce.c2, ce.c3);
298	}
299	bitmap.Palette = pal;
300	}
301	else
302	{
303	// grayscale
304	ColorPalette pal = bitmap.Palette;
305	for (int i = 0; i < 256; i++)
306	pal.Entries[i] = Color.FromArgb(255, i, i, i);
307	bitmap.Palette = pal;
308	}
309	}
310
311	// Use GDAL raster reading methods to read the image data directly into the Bitmap
312	BitmapData bitmapData = bitmap.LockBits(new Rectangle(0, 0, imageWidth, imageHeight), ImageLockMode.ReadWrite, pixelFormat);
313
314	try
315	{
316	int stride = bitmapData.Stride;
317	IntPtr buf = bitmapData.Scan0;
318
319	ds.ReadRaster(xOff, yOff, width, height, buf, imageWidth, imageHeight, dataType,
320	channelCount, bandMap, pixelSpace, stride, 1);
321	}
322	finally
323	{
324	bitmap.UnlockBits(bitmapData);
325	}
326	}
327
328	private static void SaveBitmapDirect(Dataset ds, Bitmap bitmap, int xOff, int yOff, int width, int height, int imageWidth, int imageHeight)
329	{
330	if (bitmap != null)
331	{
332	if (isIndexed)
333	{
334	// TODO: setting up the color table
335	}
336
337	// Use GDAL writing method to write the image data directly from the Bitmap
338	BitmapData bitmapData = bitmap.LockBits(new Rectangle(0, 0, imageWidth, imageHeight), ImageLockMode.ReadWrite, pixelFormat);
339
340	try
341	{
342	int stride = bitmapData.Stride;
343	IntPtr buf = bitmapData.Scan0;
344
345	ds.WriteRaster(xOff, yOff, width, height, buf, imageWidth, imageHeight, dataType,
346	channelCount, bandMap, pixelSpace, stride, 1);
347	}
348	finally
349	{
350	bitmap.UnlockBits(bitmapData);
351	}
352	}
353	}
354	}

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