Re: Why is my bitmap file smaller than it should be ? - C# Discussion Boards

Re: Why is my bitmap file smaller than it should be ?

14-Jul-09 11:47

Hi ,

I've created an 8bpp grayscale bitmap file using Bitmap.Save().
The dimensions are 504 x 480 pixels.
504 x 480 = 241920 , so I'd expect the file on the system to be at least 241920 bytes ( 8bpp )
but it's less than 1/3 that size (80,045 bytes).

Can anyone explain this to me please, it's twisting my melon man.

Christian Graus14-Jul-09 11:58

Christian Graus

14-Jul-09 11:58

You've saved it as a bitmap, not a jpg ? I would wonder if, even though you called it a .bmp, the system has defaulted to some other format.

Because, a bitmap would be three times the size you're calculating. There's no 8 bit BMP format that I know of, I thought it still stores as raw RGB data.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Re: Why is my bitmap file smaller than it should be ?

Paul Carr14-Jul-09 12:11

Re: Why is my bitmap file smaller than it should be ?

14-Jul-09 12:11

Im using the "Bitmap" class, and would have expected that to save it as a bitmap, I've read in the raw bytes, and it does seem to have an odd header (no 66,77 at the start) but it does have the grayscale RGB palette in there.

There is a PixelFormat of 8bppIndexed , but does that just relate to ImageFormat.GIF perhaps ?

Paul Carr14-Jul-09 12:13

Re: Why is my bitmap file smaller than it should be ?

14-Jul-09 12:13

What is curious though is that if I use windows explorer to look at the file I created, It shows a beautiful thumbnail ..... even though the file extension is BMP..... so the fole format must be OK.... wouldn't work if it was in GIF format.

Paul Carr14-Jul-09 12:17

Re: Why is my bitmap file smaller than it should be ?

14-Jul-09 12:17

Ah ... curious...I renamed it to BLAH.GIF and it still shows the thumbnail, I guess Bitmap.Save() default to GIF then.

harold aptroot14-Jul-09 12:20

harold aptroot

14-Jul-09 12:20

It defaults to PNG actually. That it still works is because the extension is not actually taken into account that much - the decoder will be chosen based on the actual format, not the extension.

Re: Why is my bitmap file smaller than it should be ?

harold aptroot14-Jul-09 12:19

harold aptroot

14-Jul-09 12:19

The Bitmap class really has nothing to do with bmp files - it's an in-memory representation that is based on pixels (hence the name)
If you call Save on it then the ImageFormat parameter will determine the file type (and with that I mean the actual contents of the file, not the file extension)

If you call Save without an ImageFormat it will end up as a PNG image, easily identifiable by the ‰PNG at the beginning. I think that might be what you did..

Re: Why is my bitmap file smaller than it should be ?

Christian Graus14-Jul-09 15:17

Christian Graus

14-Jul-09 15:17

It's a bitmap. That means it's an image, not a BMP. There is no JPEG class, you specify you want the JPEG format, and save the bitmap from the Bitmap class.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

using statements and IDisposable

saxisa14-Jul-09 11:38

saxisa

14-Jul-09 11:38

I'm looking at some code like this (sorry for the formatting):

public static OracleDataReader GetDynamicQueryReader (
OracleConnection con,
string sql,
out string msg)
{

sql = Regex.Replace(sql, @"\s+", " ");
try
{
using(OracleCommand cmd = new OracleCommand(sql, con))
{
cmd.CommandType = CommandType.Text;
OracleDataReader dr = cmd.ExecuteReader();
msg = "Successful";
return dr;
}
}
catch (Exception ex)
{
msg = ex.Message;
con.Close();
return null;
}
}

This little chunk (not mine) is called several thousand times, and from the profiler I am using it is the generation of a new OracleCommand object costing the most. And this object can have its parameters set after instantiation.

Normally I would make this a static, but since I am supposed to instantiate it with a using statement to deal with the disposal of unmanaged references, Im not sure I can. Can I? If I determine that there are no memory leaks with a profiler by creating and disposing some unmanaged reference, can I safely make this static? Or should I really just put up with the poor performance?

Re: using statements and IDisposable

Christian Graus14-Jul-09 11:59

Christian Graus

14-Jul-09 11:59

using and static are incompatible. In fact, if it's static, there's only ever one, and it will be disposed of when your app closes, which means there is no issue.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Re: using statements and IDisposable

PIEBALDconsult14-Jul-09 17:09

PIEBALDconsult

14-Jul-09 17:09

I create one instance of a Command as a field of a class and then re-use it as needed. I don't worry about disposing it.

work with webBrowser properties?

mr.mohsen14-Jul-09 10:16

mr.mohsen

14-Jul-09 10:16

hi friends
i want to use a one richtextbox and one webbrowser instead of a html/text editor because i dednt find any editor control that can be used in windows application,
i try to change "DocumentText" property of webBrowser control and set it with richtextbox value when user press specify button but in first time below code works correctly but in next times this property of webBrowser has not changed!!! do u know why? please tell me the solution
webBrowser1.DocumentText = richTextBox1.Text;

nobody help you...
you have to help you yourself
and this is success way.

Adam R Harris14-Jul-09 10:26

14-Jul-09 10:26

Hello Mr. Mohsen,

I replied to your original post.

but you should use the WebBrowser.Document.Body.InnerHtml to set the HTML of the document.

mr.mohsen14-Jul-09 10:39

mr.mohsen

14-Jul-09 10:39

oh no man i test your code and the result is like previouse code
in other hand both code have same result and in first time work correctly and in next times does not work
please check it to understand the problem
thank you

nobody help you...
you have to help you yourself
and this is success way.

Adam R Harris14-Jul-09 10:51

14-Jul-09 10:51

This is very strange because i just created a new project and am not experiencing your issue.

here is the sample code from my windows forms test.

public class Form1 : Form<br />
    {<br />
<br />
/// <summary><br />
        /// Required designer variable.<br />
        /// </summary><br />
        private System.ComponentModel.IContainer components = null;<br />
<br />
        /// <summary><br />
        /// Clean up any resources being used.<br />
        /// </summary><br />
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param><br />
        protected override void Dispose(bool disposing)<br />
        {<br />
            if (disposing && (components != null))<br />
            {<br />
                components.Dispose();<br />
            }<br />
            base.Dispose(disposing);<br />
        }<br />
<br />
        #region Windows Form Designer generated code<br />
<br />
        /// <summary><br />
        /// Required method for Designer support - do not modify<br />
        /// the contents of this method with the code editor.<br />
        /// </summary><br />
        private void InitializeComponent()<br />
        {<br />
            this.webBrowser1 = new System.Windows.Forms.WebBrowser();<br />
            this.button1 = new System.Windows.Forms.Button();<br />
            this.textBox1 = new System.Windows.Forms.TextBox();<br />
            this.button2 = new System.Windows.Forms.Button();<br />
            this.SuspendLayout();<br />
            // <br />
            // webBrowser1<br />
            // <br />
            this.webBrowser1.Dock = System.Windows.Forms.DockStyle.Bottom;<br />
            this.webBrowser1.Location = new System.Drawing.Point(0, 127);<br />
            this.webBrowser1.MinimumSize = new System.Drawing.Size(20, 20);<br />
            this.webBrowser1.Name = "webBrowser1";<br />
            this.webBrowser1.Size = new System.Drawing.Size(461, 257);<br />
            this.webBrowser1.TabIndex = 0;<br />
            // <br />
            // button1<br />
            // <br />
            this.button1.Dock = System.Windows.Forms.DockStyle.Top;<br />
            this.button1.Location = new System.Drawing.Point(0, 0);<br />
            this.button1.Name = "button1";<br />
            this.button1.Size = new System.Drawing.Size(461, 23);<br />
            this.button1.TabIndex = 1;<br />
            this.button1.Text = "button1";<br />
            this.button1.UseVisualStyleBackColor = true;<br />
            this.button1.Click += new System.EventHandler(this.button1_Click);<br />
            // <br />
            // textBox1<br />
            // <br />
            this.textBox1.Location = new System.Drawing.Point(22, 30);<br />
            this.textBox1.Name = "textBox1";<br />
            this.textBox1.Size = new System.Drawing.Size(377, 20);<br />
            this.textBox1.TabIndex = 2;<br />
            // <br />
            // button2<br />
            // <br />
            this.button2.Location = new System.Drawing.Point(0, 56);<br />
            this.button2.Name = "button2";<br />
            this.button2.Size = new System.Drawing.Size(461, 23);<br />
            this.button2.TabIndex = 3;<br />
            this.button2.Text = "button2";<br />
            this.button2.UseVisualStyleBackColor = true;<br />
            this.button2.Click += new System.EventHandler(this.button2_Click);<br />
            // <br />
            // Form1<br />
            // <br />
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);<br />
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;<br />
            this.ClientSize = new System.Drawing.Size(461, 384);<br />
            this.Controls.Add(this.button2);<br />
            this.Controls.Add(this.textBox1);<br />
            this.Controls.Add(this.button1);<br />
            this.Controls.Add(this.webBrowser1);<br />
            this.Name = "Form1";<br />
            this.Text = "Form1";<br />
            this.Load += new System.EventHandler(this.Form1_Load);<br />
            this.ResumeLayout(false);<br />
            this.PerformLayout();<br />
<br />
        }<br />
<br />
        #endregion<br />
<br />
        private System.Windows.Forms.WebBrowser webBrowser1;<br />
        private System.Windows.Forms.Button button1;<br />
        private System.Windows.Forms.TextBox textBox1;<br />
        private System.Windows.Forms.Button button2;<br />
<br />
<br />
        public Form1()<br />
        {<br />
            InitializeComponent();<br />
        }<br />
<br />
        private void Form1_Load(object sender, EventArgs e)<br />
        {<br />
            this.webBrowser1.Navigate("about:blank");<br />
        }<br />
<br />
        private void button1_Click(object sender, EventArgs e)<br />
        {<br />
            this.webBrowser1.Document.Body.InnerHtml += "<br />Clicked!";<br />
        }<br />
<br />
        private void button2_Click(object sender, EventArgs e)<br />
        {<br />
            this.webBrowser1.Document.Body.InnerHtml += "<br />" + this.textBox1.Text;<br />
        }<br />
    }

All i did was add the WebBrowser control the form, i then added 2 buttons and a textbox.
when the user clicks the button "Clicked!" is appended to the text when they click the other button the text in the text box is inserted.

If you want to test it just add a new class your existing project and paste all the sample code in there then set it as your startup object.

mr.mohsen14-Jul-09 20:19

mr.mohsen

14-Jul-09 20:19

thank you my friend
your code work correctly
the problem is i didnt call navigate methode of webBrowser with about:blank value parameter
thank you very mutch

nobody help you...
you have to help you yourself
and this is success way.

Adam R Harris14-Jul-09 20:28

RegEx not finding matches ... but it should

14-Jul-09 20:28

Guess I should have mentioned that.
Well good to hear you got it working.

Adam R Harris14-Jul-09 9:46

Re: RegEx not finding matches ... but it should

14-Jul-09 9:46

Hey All,

I am experiencing a strange issue, i have built and tested my RegEx in Expresso but when I call it from my code (C#) I am not getting any matches. If i step through and grab the values from the variables and put those in Expresso it works ....

RegEx:

Lead\sID\sNumber:\s*(?<LeadNumber>[^\r\n]*)(?:\r\n)+<br />
Prospect\sName:.*(?:\r\n)+<br />
Prospect\sContact:.*(?:\r\n)+<br />
Prospect\sPhone:.*(?:\r\n)+<br />
Marketing\sCampaign:.*(?:\r\n)+<br />
Prospect\sInformation:\s*(?:\r\n)+<br />
===============\s(?:\r\n)+<br />
(?<Company>[^\r\n]*)(?:\r\n)+<br />
(?<Address1>[^,]*),\s(?<Address2>[^\r\n]*)(?:\r\n)+<br />
(?<City>[^,]*),\s(?<State>[^\r\n]*)(?:\r\n)+<br />
(?<Country>[^,]*),\s(?<Zip>[^\r\n]*)(?:\r\n)+<br />
Contact\sName:\s*(?<FirstName>[^\s]*)\s(?<LastName>[^\r\n]*)(?:\r\n)+<br />
Contact\sPhone:\s*(?<Phone>[^\r\n]*)(?:\r\n)+

C#:

<br />
MatchCollection myMatches = Regex.Matches([Text], [RegEx], RegexOptions.Multiline | RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.IgnorePatternWhitespace | RegexOptions.CultureInvariant);<br />

[Text] = the body of an email
[RegEx] = the above pattern

Any input or ideas would be greatly appreciated.

dan!sh 14-Jul-09 19:53

dan!sh

14-Jul-09 19:53

If you can provide some sample text that this Regex should match, it might help.

Re: RegEx not finding matches ... but it should

Adam R Harris14-Jul-09 19:59