Increase and decrease colour contrast of an Image c#

Question

HI Guys ,

Thanks for your quick response for my previous posts ...I need your help again

I am working with a web application in c#..I need to increase and decrease the color contrast of an Image using the scroll bar..please post the code as soon as possible

Balaji Essakki · Answer

no still i am getting the same error

Raaj Kumar · Answer

Hi, It seems there is no problem in code. Could you please check the permission of the folder for read/write operation if you have hosted in IIS. Otherwise Right-Click on MembershipImages folder and uncheck the readonly property. Since if you dont have permission it will throw this error. Regards, raaj

Balaji Essakki · Answer

Although i was using the same filename its not working using System; using System.Collections; using System.Configuration; using System.Data; using System.Linq; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Xml.Linq; using System.Drawing; using System.Drawing.Imaging; using System.IO; public partial class slider : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Image1.ImageUrl = "MembershipImages/Sample.jpg"; } protected void txtBrightness_TextChanged(object sender, EventArgs e) { string filename = Server.MapPath("MembershipImages/brightImage.jpg"); AdjustBrightness(filename, Convert.ToInt16(txtBrightness.Text)); } protected void txtContrast_TextChanged(object sender, EventArgs e) { string filename = Server.MapPath("MembershipImages/brightImage.jpg"); AdjustContrast(filename, Convert.ToSByte(txtContrast.Text)); } #region Core public void AdjustBrightness(string fileName, int Value) { Bitmap oBitmap = default(Bitmap); oBitmap = new Bitmap(fileName); Graphics oGraphic = default(Graphics); Bitmap bmpNew = new Bitmap(oBitmap.Width, oBitmap.Height); oGraphic = Graphics.FromImage(bmpNew); float FinalValue = (float)Value / 255.0f; float[][] FloatColorMatrix ={ new float[] {1, 0, 0, 0, 0}, new float[] {0, 1, 0, 0, 0}, new float[] {0, 0, 1, 0, 0}, new float[] {0, 0, 0, 1, 0}, new float[] {FinalValue, FinalValue, FinalValue, 1, 1} }; ColorMatrix NewColorMatrix = new ColorMatrix(FloatColorMatrix); ImageAttributes Attributes = new ImageAttributes(); Attributes.SetColorMatrix(NewColorMatrix); oGraphic.DrawImage(oBitmap, new Rectangle(0, 0, bmpNew.Width, bmpNew.Height), 0, 0, oBitmap.Width, oBitmap.Height, GraphicsUnit.Pixel, Attributes); oBitmap.Dispose(); oBitmap = bmpNew; oGraphic.Dispose(); oBitmap.Save(fileName, ImageFormat.Jpeg); oBitmap.Dispose(); } public void AdjustContrast(string fileName, float Value) { Bitmap oBitmap = default(Bitmap); oBitmap = new Bitmap(fileName); Graphics oGraphic = default(Graphics); Bitmap bmpNew = new Bitmap(oBitmap.Width, oBitmap.Height); oGraphic = Graphics.FromImage(bmpNew); float FinalValue = (float)Value / 255.0f; float[][] FloatColorMatrix ={ new float[] {Value, 0f, 0f, 0f, 0f}, new float[] {0f, Value, 0f, 0f, 0f}, new float[] {0f, 0f, Value, 0f, 0}, new float[] {0f, 0f, 0f, 1f, 0f}, new float[] {0.001f, 0.001f, 0.001f, 0f, 1f} }; ColorMatrix NewColorMatrix = new ColorMatrix(FloatColorMatrix); ImageAttributes Attributes = new ImageAttributes(); Attributes.SetColorMatrix(NewColorMatrix); oGraphic.DrawImage(oBitmap, new Rectangle(0, 0, bmpNew.Width, bmpNew.Height), 0, 0, oBitmap.Width, oBitmap.Height, GraphicsUnit.Pixel, Attributes); oBitmap.Dispose(); oBitmap = bmpNew; oGraphic.Dispose(); oBitmap.Save(fileName, ImageFormat.Jpeg); oBitmap.Dispose(); } public void AdjustContrast(Bitmap Image, float Value, string tofileName) { Value = (100.0f + Value) / 100.0f; Value *= Value; System.Drawing.Bitmap TempBitmap = Image; System.Drawing.Bitmap NewBitmap = new System.Drawing.Bitmap(TempBitmap.Width, TempBitmap.Height); System.Drawing.Graphics NewGraphics = System.Drawing.Graphics.FromImage(NewBitmap); NewGraphics.DrawImage(TempBitmap, new System.Drawing.Rectangle(0, 0, TempBitmap.Width, TempBitmap.Height), new System.Drawing.Rectangle(0, 0, TempBitmap.Width, TempBitmap.Height), System.Drawing.GraphicsUnit.Pixel); NewGraphics.Dispose(); for (int x = 0; x { for (int y = 0; y { Color Pixel = NewBitmap.GetPixel(x, y); float Red = Pixel.R / 255.0f; float Green = Pixel.G / 255.0f; float Blue = Pixel.B / 255.0f; Red = (((Red - 0.5f) * Value) + 0.5f) * 255.0f; Green = (((Green - 0.5f) * Value) + 0.5f) * 255.0f; Blue = (((Blue - 0.5f) * Value) + 0.5f) * 255.0f; NewBitmap.SetPixel(x, y, Color.FromArgb(Clamp((int)Red, 255, 0), Clamp((int)Green, 255, 0), Clamp((int)Blue, 255, 0))); } } FileInfo imgFile = new FileInfo(tofileName); NewBitmap.Save(imgFile.OpenWrite(), System.Drawing.Imaging.ImageFormat.Jpeg); imgFile = null; NewBitmap.Dispose(); } public T Clamp (T value, T max, T min) where T : System.IComparable { T result = value; if (value.CompareTo(max) > 0) result = max; if (value.CompareTo(min) result = min; return result; } #endregion private void ReadWriteStream(string filePath) { byte[] buffer; FileStream fStream = new FileStream(filePath, FileMode.Open, FileAccess.Read); try { int length = (int)fStream.Length; buffer = new byte[length]; int count, sum = 0; while ((count = fStream.Read(buffer, sum, length - sum)) > 0) { sum += count; } } catch (Exception ex) { Response.Write(ex.Message); } finally { fStream.Close(); fStream.Dispose(); } } }

Raaj Kumar · Answer

Hi, For me it is working. Could you please post the code so that I can tell you what exaclty to be done? Regards, Raaj

Balaji Essakki · Answer

still i am getting the same error...If i give the file name which is already in the folder means same error occurs..if i give a new file name means its showing invalid parameter

Raaj Kumar · Answer

Hi, Check this application. It is because I didn't handle the object disposal properly. Now it is done. Here I have overwritten the existing image with processed image. For your convenience you can store it in separate file. Regards, raaj

Balaji Essakki · Answer

but there is an error occurs while saving the bitmap to tofilename A generic error occurred in GDI+.

Raaj Kumar · Answer

If it helps could you please mark it as an answer?

Balaji Essakki · Answer

Thanks a lot Raaj...

Raaj Kumar · Answer

Hi, You can refer the similar post which I have answered. http://www.c-sharpcorner.com/Forums/ShowMessages.aspx?ThreadID=79909 But there is no scrollbar instead Ajax SliderControl is used. However you can make use of the logic behind that. Regards, raaj

Increase and decrease colour contrast of an Image c#

Answers (10)