Best Way To Clear All Pixels In A Bitmap?
Aug 28, 2009Was just wondering if there is a way to quickly clear all pixels in a bitmap without creating a new one?
View 1 RepliesWas just wondering if there is a way to quickly clear all pixels in a bitmap without creating a new one?
View 1 RepliesMy goal is to iterate through each pixel determining whether it is black or white. Ideally I want to do this one row at a time (so I can count the number of black pixels in each row). This is a bitonal image.I tried to get it started, but I don't understand what value(s) I'm supposed to be polling for. The following code takes a stab at it (i.e. makes a guess as to what value I'm supposed to check) and then outputs that value to a textfile.When I read the textfile, though, it doesn't look like anything useful.This code is an attempted modification of some code found in a CodeProject article.[code]
View 5 Repliesi mostly use C and assembly, but i thought i would give VB.NET a shot. i used to use VB6 all the time, so wanted to see how different this is. in VB2010, i'm trying to modify the pixels of a Bitmap object and then make it show up in a PictureBox on the form. i get no errors, but this code does not show the new bitmap after it runs.."disp" is the name of the PictureBox on the form.[code]
View 1 RepliesPretty self-explanatory question. I'm trying to see if I can do sprite animation in Visual Basic and, while I can use a Graphics object to translate a bitmap down a few pixels, I have absolutely no idea how to erase the bitmap drawn in its former position. Is there any way to erase the old image before the new image is drawn onto the form?
View 14 RepliesI have scanned a few img's on 600 DPI. When i load them into a Bitmap class They have Vertical and Horizontal Resolution of 96 PPI To my calculation that is very close to 38 Pixels per centimeter. Now the image that I scanned is 4.5 Centimeter (1.77165354 Inch) In Diameter but When I measure It the 4.5 cm img is close to 1080 pixel in Diameter which is 240 Pixels/Centimeter (609.6 Pixels/inch) What is the correct way to get the actual Pixels per inch/centimeter from a bitmap or was it set incorrectly by my scanner ?
View 7 RepliesI've been trying to mess around with image recognition in C# for some time now. But to do that, I need acces to all the pixels in the bitmap individually. At the moment, I'm using getPixel and setPixel. It works, but it's VERY slow. Is there any faster way to acces pixels in a bitmap? Unsafe code maybe?
View 6 RepliesPrivate Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim cr As New Bitmap(4, 4)
[code]......
I need to write a code to find identical adjacent pixels in a bitmap image. It should work as the 'magical wand' in Photoshop. My images are always black and white (white background with car parts drawed in black). Given the x,y coordinate for a single black pixel in the whole image, the code should find (and paint with another color, say red) all other black pixels that are linked to that one, and so on, until all linked black points will be painted in red.
[Code]...
I need to write a code to find identical adjacent pixels in a bitmap image. It should work as the 'magical wand' in Photoshop.My images are always black and white (white background with car parts drawed in black). Given the x,y coordinate for a single black pixel in the whole image, the code should find (and paint with another color, say red) all other black pixels that are linked to that one, and so on, until all linked black points will be painted in red.This way, suppose that I have an image with 4 car parts drawed, then if I give the x,y coordinate of a black pixel, just THAT part to whose the black pixel belongs to should be painted in red. All other parts will remain black. Does it make sense?At the end, there are two pictures (before and after) to help understanding what I need to do to the images.I tried a simple 8-pixel adjacent approach for every pixel (starting on initial coordinate) but it turns out into a very stupid and endless looping algorhitm.
Code:
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms
[code]....
I've created a bitmap on which I use setpixel to color it in. Then I display it on a picturebox. I want to clear the bitmap form time to time, reset all its pixels. I see no bitmap.clear() method and there's nothing in the documentation that seems. Short of disposing of or setting the bitmap = nothing and creating a new one, how do I wipe a bitmap?
View 8 RepliesI'm trying to make a -what i thought would be simple app.My intention was to build program that:1) i'd provide a grayscale image2) the program would count the black pixels the grey pixels the more grey pixels etc. (the hue) and the white3) would make the percentage sum of all pixels, that is: 300.000 black pixels (rgb 0 0 0) etc. given that 0 is the black, 100 the white. e.g a simple grayscale image is 55.2 white
This was my way and i don't think that is useful:
First of a button to convert the image to greyscale:
Dim bm as new Bitmap(source.Width,source.Height)
Dim x
Dim y
[CODE]...
Secondly, -and that's the stupid way- i did -or better i wanted to do- this: i put the code to dynamically create labels, each label having the colour of a pixel as background colour and as text the colour converted to rgb
The third step which i intended to do (i couldn't get pas two) was to sum up the labels etc.
I'm using Bitmap to show picture box like slideshow using Timer. For each timer interval, I've to go for new instance of Bitmap, there System memory increases to 1MB, How to resolve this, 'BG is picture box
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tic Dim img As Bitmap
img = New Bitmap(System.Drawing.Bitmap.FromFile(FileIO.FileSystem.GetFiles
[CODE]...
I'm trying to use a ToolTip directly to a Bitmap Object (System.Drawing.Bitmap), aparently I can't do this because Bitmap isnt a Windows Control.
View 1 Replieshow can i create a monochrome bitmap from a semi transparent bitmap in vb.net? the bmp is for a transparency mask image for an icon i'm trying to create with the CreateIconIndirect API function.
i'm using vb2008 .Net3.5, but i would prefer an answer that would also work in vb2005
this is currently my code to clear my 5 textboxes
Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
TextBox1.Clear()
TextBox2.Clear()
TextBox3.Clear()
TextBox4.Clear()
TextBox5.Clear()
End Sub
Here is a short program to demonstrate my question. I just want to extraxct a rectangle bitmap from a big bitmap.Code as follows:
Private
Sub Button3_Click(ByVal sender
As System.Object,[code]....
Execution stops when hitting the Dim cloneBitmap statement, which should have created a bitmap out of the rectangle cut out.The message is:
"MissingMemeberException was unhandled.
No default member was found for type 'bitmap"
I just don't get it. Seems that the method Clone(Rectangle, PixelFormat was not found.
I have a grass image located here in my directory. I want to just create a Bitmap, but I am getting an error. (Parameter is not valid.) Immediate Window: A first chance exception of type 'System.ArgumentException' occurred in System.Drawing.dll
[URL]
private void Form1_Load(object sender, EventArgs e)
{
Bitmap bmp = new Bitmap("grass.jpg");
}
bertino
i have a problem with the Size in VB.Net I think the Control Size in VB.Net Is Pixels so I want to enter this size cm/inch
I want To Convert Pixels to cm/inch or cm/inch to Pixels
I have a timer that runs every time by itself, and for the code the runs in it I would like to have it clear the dataset before it does anything, the timer runs every 10 seconds, so I tried to do dataset.clear but it would crash if the dataset had no values
View 4 Repliesin hyper teriminal when i press "ctrl+L" is to clear terminal screen how to write the code in vb.net? Hyperterminal is connecting to serial comport.when i try this it work and return line on debug
serialport.writeline ("at+cmgl=1")
i try this but not work and it still show some lines on debug
serialport.writeline (vbcrtl +"L")
serialport.WriteLine("vbCrLf + l")
way to clear textboxes in VB.Net and what is the difference between the two methods? I have also seen people be critical of folk using clear objects on their forms and i can see why but in this case, i am only learning.
txtbox1.Clear()
or
txtbox1.Text = ""
wan to ask about anyone know the code about how to clear all the data inside the data grid view without clear the binding source...
View 1 RepliesThe code below reads an Icon from an .ico file, converts the Icon read to a Bitmap and saves the bitmap using:
Bitmap.Save(PathA)
Then does:
PanelShowWrittenIconA.BackgroundImage = New Bitmap(PathA)
[code].....
In my winform program (in vb.net) I wrote:
Dim dt As New DataTable
'Get data from DB into dt
'...
[Code].....
But when I run the program, Clear() cleared both dt and dttemp! Why? Aren't dt and dttemp supposed to be two distinct instances of DataTable?
(I finally found a solution - dttemp = dt.Copy() instead of dttemp = dt. But I still can't see why Copy() was necessary in this case.
i`m trying to find in cm or mm the area of a frame (capture image).The picturebox has dimensions height:456 and width:553 PIXELS.So the total number of pixels are 456 x 553 = 252,168
If i compare image 1 with image 2 i can locate and draw a rectangle around that area of pixels that are different.i can get the width and the height of this rectangle in PIXELS.e.g Height:49 Width:33 PIXELS
How can i covert these into cm or mm. What i need to know for the conversion?
I know dpi: dots per inch but what`s the value for my rectangle?
I am using the StreamWriter to create a log file for my application. However I do not see a method on how to clear the file (make the file blank again). Also before I clear the file I want to rename it so that I can have multiple log files, a new one produced everytime the application runs.
[Code]...
I would like to believe that this code will display a horizontal line halfway across the PictureBox pbxData. In fact, what it does is create the BitMap and then blow up with a memory violation when trying to copy the BitMap into the PictureBox. The code that alters the array is commented out because I don't know how to address the elements of the array.
how to make this into useful code?
Imports System.Runtime.InteropServices
Public Class Form1
Private b1 As Bitmap
[Code].....
How can we get the pixels of an image in a fast way?
View 1 RepliesIs there a way of converting pixels to points? The dimensions in VB are in pixels, but Office COM such as WordApp.Resize are expressed in points. So trying to align app windows is a mess.I guess the ratio of pixels to points varies from one monitor to another(?), so this would need to be calculated at run time.I tried a nifty trick of doing Me.Font.SizeInPoints / Me.FontHeight but that doesnt seem to be quite right or a very sensible way of doing it.
View 2 Replieshow can i get a full code or full information how to work with image and pixels i want to work with image by pixels as integer number not as color?
View 5 Replies