I have the request that crop image white space in C#, and I search some methods from the forum, but it could not satisfy my request.
There is the original image,
This is the result I expect,
Any help are appreciate.
You can try to get first image data(There is an image), and draw the data into a new image. Try this method. Hope it can help you.
private static Bitmap ImageTrim(Bitmap img)
{
//get image data
BitmapData bd= img.LockBits(new Rectangle(Point.Empty, img.Size),
ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
int[] rgbValues = new int[img.Height * img.Width];
Marshal.Copy(bd.Scan0, rgbValues, 0, rgbValues.Length);
img.UnlockBits(bd);
#region determine bounds
int left = bd.Width;
int top = bd.Height;
int right = 0;
int bottom = 0;
//determine top
for (int i = 0; i < rgbValues.Length; i++)
{
int color = rgbValues[i] & 0xffffff;
if (color != 0xffffff)
{
int r = i / bd.Width;
int c = i % bd.Width;
if (left > c)
{
left = c;
}
if (right < c)
{
right = c;
}
bottom = r;
top = r;
break;
}
}
//determine bottom
for (int i = rgbValues.Length - 1; i >= 0; i--)
{
int color = rgbValues[i] & 0xffffff;
if (color != 0xffffff)
{
int r = i / bd.Width;
int c = i % bd.Width;
if (left > c)
{
left = c;
}
if (right < c)
{
right = c;
}
bottom = r;
break;
}
}
if (bottom > top)
{
for (int r = top + 1; r < bottom; r++)
{
//determine left
for (int c = 0; c < left; c++)
{
int color = rgbValues[r * bd.Width + c] & 0xffffff;
if (color != 0xffffff)
{
if (left > c)
{
left = c;
break;
}
}
}
//determine right
for (int c = bd.Width - 1; c > right; c--)
{
int color = rgbValues[r * bd.Width + c] & 0xffffff;
if (color != 0xffffff)
{
if (right < c)
{
right = c;
break;
}
}
}
}
}
int width = right - left + 1;
int height = bottom - top + 1;
#endregion
//copy image data
int[] imgData = new int[width * height];
for (int r = top; r <= bottom; r++)
{
Array.Copy(rgbValues, r * bd.Width + left, imgData, (r - top) * width, width);
}
//create new image
Bitmap newImage = new Bitmap(width, height, PixelFormat.Format32bppArgb);
BitmapData nbd
= newImage.LockBits(new Rectangle(0, 0, width, height),
ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
Marshal.Copy(imgData, 0, nbd.Scan0, imgData.Length);
newImage.UnlockBits(nbd);
return newImage;
}
If your image only has 2 colors (white and black), you can iterate through your image and find the top left pixel set and the bottom right pixel set, then you can crop it:
(pseudo code, depends on what you use to get your image pixels)
int minX = int.MaxValue, maxX = 0, minY = int.MaxValue, maxY = 0;
for (x = 0; x < image.Width, x++)
{
for (y = 0; y < image.Height; y++)
{
if (image[x, y] == 1)
{
if (x < minX) minX = x;
else if (x > maxX) maxX = x;
if (y < minY) minY = y;
else if (y > maxY) maxY = y;
}
}
}
then you'll have the coordinates that will let you crop the image
I'm sure this could be optimized but that's the general idea
Related
I'm currently in the development phase of a photoconverter program and in the process of developing a blur filter. At the initial stages of prototyping this feature, i devised a algorithm in which I had an accumulator for each color channel and add all the pixels in a radius of the target pixel. Afterwards the program would divide the accum by the amount of pixels read(not counting those offscreen). At first I thought this would be fine but when it started to work, I had the problem of this filter taking an hour to render with this being the result at the lowest setting. So I opted to utilize parallel processing in C# to make this process much easier and faster to run. With the boost of speed came the cost of the image becoming very glitched out. Here's the image before, and Here's the image afterwards
This is the code I wrote for the filter
public static DirectBitmap NewBlur (DirectBitmap image, int radius)
{
int sectorDiam = 128;
DirectBitmap newimage = image;
List<Rectangle> renderSectors = new List<Rectangle>();
Rectangle rect;
for (int x = 0; x < (image.Width / sectorDiam); x++)
{
int xwidth = sectorDiam;
for (int y = 0; y < (image.Height / sectorDiam); y++)
{
int yheight = sectorDiam;
rect = new Rectangle(x * sectorDiam, y * sectorDiam, xwidth, yheight);
renderSectors.Add(rect);
}
}
var Picrect = new Rectangle(0, 0, image.Width, image.Height);
var data = image.Bitmap.LockBits(Picrect, ImageLockMode.ReadWrite, image.Bitmap.PixelFormat);
var depth = Bitmap.GetPixelFormatSize(data.PixelFormat) / 8; //bytes per pixel
var buffer = new byte[data.Width * data.Height * depth];
Marshal.Copy(data.Scan0, buffer, 0, buffer.Length);
Parallel.ForEach(renderSectors, sector =>
{
BlurSection(buffer, sector, Picrect, radius, image.Width, image.Height, depth);
}
);
Marshal.Copy(buffer, 0, data.Scan0, buffer.Length);
image.Bitmap.UnlockBits(data);
return image;
}
And here's the method for each section of the image to be blurred.
public static void BlurSection(byte[] buffer, Rectangle blurSector, Rectangle bitmaprect, int radius, int width, int height, int depth)
{
int[] Accum = new int[4];
for (int x = blurSector.X; x < blurSector.Width+ blurSector.X; x++)
{
for (int y = blurSector.Y; y < blurSector.Height + blurSector.Y; y++)
{
Accum[0] = 0;
Accum[1] = 0;
Accum[2] = 0;
Accum[3] = 0;
for (int i = -radius; i <= radius; i++)
{
for (int j = -radius; j <= radius; j++)
{
var offset = 0;
offset = (((y+j) * width) + (x+i)) * depth;
if (bitmaprect.Contains(new Point(x + i, y + j))){
Accum[0] += buffer[offset + 0];
Accum[1] += buffer[offset + 1];
Accum[2] += buffer[offset + 2];
Accum[3]++;
}
}
}
Accum[0] = Accum[0] / Accum[3];
if (Accum[0] > 255)
{
Accum[0] = 255;
}
Accum[1] = Accum[1] / Accum[3];
if (Accum[1] > 255)
{
Accum[1] = 255;
}
Accum[2] = Accum[2] / Accum[3];
if (Accum[2] > 255)
{
Accum[2] = 255;
}
var newoffset = ((y * width) + (x * depth*2));
buffer[newoffset + 0] = (byte)Accum[0];
buffer[newoffset + 1] = (byte)Accum[1];
buffer[newoffset + 2] = (byte)Accum[2];
}
}
}
It's also worth noting that I'm using a Bitmap class to make access to pixel data much easier, the "DirectBitmap" you can find here: https://stackoverflow.com/a/34801225/15473435. Is there anything that I'm missing or not aware of that's causing this algorithm not to function?
I am trying to get color from specific area in an Image.
Assume that , this is image , and I want to get color inside image.(the result should be red of the above image) This color may be different position in image. Because I don't know exact position of color where it starting, so I can't get exact result.
Until now, I cropped image giving manually position of x and y, and then cropped image and I got average color of cropped image. But I know , this is not exact color.
What I tried :
private RgbDto GetRGBvalueCroppedImage(Image croppedImage)
{
var avgRgb = new RgbDto();
var bm = new Bitmap(croppedImage);
BitmapData srcData = bm.LockBits(
new Rectangle(0, 0, bm.Width, bm.Height),
ImageLockMode.ReadOnly,
PixelFormat.Format32bppArgb);
int stride = srcData.Stride;
IntPtr Scan0 = srcData.Scan0;
long[] totals = new long[] { 0, 0, 0 };
int width = bm.Width;
int height = bm.Height;
unsafe
{
byte* p = (byte*)(void*)Scan0;
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
for (int color = 0; color < 3; color++)
{
int idx = (y * stride) + x * 4 + color;
totals[color] += p[idx];
}
}
}
}
avgRgb.avgB = (int)totals[0] / (width * height);
avgRgb.avgG = (int)totals[1] / (width * height);
avgRgb.avgR = (int)totals[2] / (width * height);
return avgRgb;
}
How can I get exact position to crop? May be I can convert image to byte array, then I can find different color and take position of it and then crop. But I have no clue how do this.
You can use something this extension method to get dominant color in a region of an image in case they are not all the same
public static Color GetDominantColor(this Bitmap bitmap, int startX, int startY, int width, int height) {
var maxWidth = bitmap.Width;
var maxHeight = bitmap.Height;
//TODO: validate the region being requested
//Used for tally
int r = 0;
int g = 0;
int b = 0;
int totalPixels = 0;
for (int x = startX; x < (startX + width); x++) {
for (int y = startY; y < (startY + height); y++) {
Color c = bitmap.GetPixel(x, y);
r += Convert.ToInt32(c.R);
g += Convert.ToInt32(c.G);
b += Convert.ToInt32(c.B);
totalPixels++;
}
}
r /= totalPixels;
g /= totalPixels;
b /= totalPixels;
Color color = Color.FromArgb(255, (byte)r, (byte)g, (byte)b);
return color;
}
You can then use it like
Color pixelColor = myBitmap.GetDominantColor(xPixel, yPixel, 5, 5);
there is room for improvement, like using a Point and Size, or even a Rectangle
public static Color GetDominantColor(this Bitmap bitmap, Rectangle area) {
return bitmap.GetDominantColor(area.X, area.Y, area.Width, area.Height);
}
and following this link:
https://www.c-sharpcorner.com/UploadFile/0f68f2/color-detecting-in-an-image-in-C-Sharp/
If you want to get the image colors, you don't need to do any cropping at all. Just loop on image pixels and find the two different colors. (Assuming that you already know the image will have exactly 2 colors, as you said in comments). I've written a small function that will do that. However, I didn't test it in an IDE, so expect some small mistakes:
private static Color[] GetColors(Image image)
{
var bmp = new Bitmap(image);
var colors = new Color[2];
colors[0] = bmp.GetPixel(0, 0);
for (int i = 0; i < bmp.Width; i++)
{
for (int j = 0; j < bmp.Height; j++)
{
Color c = bmp.GetPixel(i, j);
if (c == colors[0]) continue;
colors[1] = c;
return colors;
}
}
return colors;
}
enter image description here
Please give me a solution about that I have ti find out many site's but i did not get any solution.
thankyou
private void Form1_Load(object sender, EventArgs e)
{
Bitmap bitmap = new Bitmap(#"D:\shapes_Images\4.png");
pictureBox1.Image = bitmap;
image = bitmap ;
}
Bitmap image;
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
//Create a path and add lines.
List<Point> outlinePoints = new List<Point>();
BitmapData bitmapData = image.LockBits(new Rectangle(0, 0, image.Width, image.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
byte[] originalBytes = new byte[image.Width * image.Height * 4];
Marshal.Copy(bitmapData.Scan0, originalBytes, 0, originalBytes.Length);
//find non-transparent pixels visible from the top of the image
for (int x = 0; x < bitmapData.Width; x++)
{
for (int y = 0; y < bitmapData.Height; y++)
{
byte alpha = originalBytes[y * bitmapData.Stride + 4 * x + 3];
if (alpha != 0)
{
Point p = new Point(x, y);
if (!ContainsPoint(outlinePoints, p))
outlinePoints.Add(p);
break;
}
}
}
//helper variable for storing position of the last pixel visible from both sides
//or last inserted pixel
int? lastInsertedPosition = null;
//find non-transparent pixels visible from the right side of the image
for (int y = 0; y < bitmapData.Height; y++)
{
for (int x = bitmapData.Width - 1; x >= 0; x--)
{
byte alpha = originalBytes[y * bitmapData.Stride + 4 * x + 3];
if (alpha != 0)
{
Point p = new Point(x, y);
if (!ContainsPoint(outlinePoints, p))
{
if (lastInsertedPosition.HasValue)
{
outlinePoints.Insert(lastInsertedPosition.Value + 1, p);
lastInsertedPosition += 1;
}
else
{
outlinePoints.Add(p);
}
}
else
{
//save last common pixel from visible from more than one sides
lastInsertedPosition = outlinePoints.IndexOf(p);
}
break;
}
}
}
lastInsertedPosition = null;
//find non-transparent pixels visible from the bottom of the image
for (int x = bitmapData.Width - 1; x >= 0; x--)
{
for (int y = bitmapData.Height - 1; y >= 0; y--)
{
byte alpha = originalBytes[y * bitmapData.Stride + 4 * x + 3];
if (alpha != 0)
{
Point p = new Point(x, y);
if (!ContainsPoint(outlinePoints, p))
{
if (lastInsertedPosition.HasValue)
{
outlinePoints.Insert(lastInsertedPosition.Value + 1, p);
lastInsertedPosition += 1;
}
else
{
outlinePoints.Add(p);
}
}
else
{
//save last common pixel from visible from more than one sides
lastInsertedPosition = outlinePoints.IndexOf(p);
}
break;
}
}
}
lastInsertedPosition = null;
//find non-transparent pixels visible from the left side of the image
for (int y = bitmapData.Height - 1; y >= 0; y--)
{
for (int x = 0; x < bitmapData.Width; x++)
{
byte alpha = originalBytes[y * bitmapData.Stride + 4 * x + 3];
if (alpha != 0)
{
Point p = new Point(x, y);
if (!ContainsPoint(outlinePoints, p))
{
if (lastInsertedPosition.HasValue)
{
outlinePoints.Insert(lastInsertedPosition.Value + 1, p);
lastInsertedPosition += 1;
}
else
{
outlinePoints.Add(p);
}
}
else
{
//save last common pixel from visible from more than one sides
lastInsertedPosition = outlinePoints.IndexOf(p);
}
break;
}
}
}
// Added to close the loop
outlinePoints.Add(outlinePoints[0]);
image.UnlockBits(bitmapData);
GraphicsPath myPath = new GraphicsPath();
myPath.AddLines(outlinePoints.ToArray());
// return outlinePoints.ToArray();
PathGradientBrush pthGrBrush = new PathGradientBrush(outlinePoints.ToArray());
//foreach (Point p in outlinePoints.ToArray())
//{
// //Point p1 = p;
//}
Color[] colors = { Color.Red , Color.Green };
pthGrBrush.SurroundColors = colors;
pthGrBrush.CenterColor = Color.Red;
Blend blend = new Blend();
// blend.Factors = new float[] { 1, 0 };
blend.Positions = new float[] { 0, 0.25f };
pthGrBrush.Blend = blend;
// LinearGradientBrush linGrBrush = new LinearGradientBrush(new Point(0, 10),new Point(200, 10),Color.FromArgb(255, 255, 0, 0),Color.FromArgb(255, 0, 0, 255));
e.Graphics.FillPath(pthGrBrush, myPath);
// Pen myPen = new Pen(Color.Black, 6);
// e.Graphics.DrawPath(pthGrBrush, myPath);
}
I'm using the following code to remove whitespace around an image.
static Bitmap TrimBitmap(Bitmap source)
{
Rectangle srcRect = default(Rectangle);
BitmapData data = null;
try
{
data = source.LockBits(new Rectangle(0, 0, source.Width, source.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
byte[] buffer = new byte[data.Height * data.Stride];
Marshal.Copy(data.Scan0, buffer, 0, buffer.Length);
int xMin = int.MaxValue,
xMax = int.MinValue,
yMin = int.MaxValue,
yMax = int.MinValue;
bool foundPixel = false;
// Find xMin
for (int x = 0; x < data.Width; x++)
{
bool stop = false;
for (int y = 0; y < data.Height; y++)
{
byte alpha = buffer[y * data.Stride + 4 * x + 3];
if (alpha != 0)
{
xMin = x;
stop = true;
foundPixel = true;
break;
}
}
if (stop)
break;
}
// Image is empty...
if (!foundPixel)
return null;
// Find yMin
for (int y = 0; y < data.Height; y++)
{
bool stop = false;
for (int x = xMin; x < data.Width; x++)
{
byte alpha = buffer[y * data.Stride + 4 * x + 3];
if (alpha != 0)
{
yMin = y;
stop = true;
break;
}
}
if (stop)
break;
}
// Find xMax
for (int x = data.Width - 1; x >= xMin; x--)
{
bool stop = false;
for (int y = yMin; y < data.Height; y++)
{
byte alpha = buffer[y * data.Stride + 4 * x + 3];
if (alpha != 0)
{
xMax = x;
stop = true;
break;
}
}
if (stop)
break;
}
// Find yMax
for (int y = data.Height - 1; y >= yMin; y--)
{
bool stop = false;
for (int x = xMin; x <= xMax; x++)
{
byte alpha = buffer[y * data.Stride + 4 * x + 3];
if (alpha != 0)
{
yMax = y;
stop = true;
break;
}
}
if (stop)
break;
}
srcRect = Rectangle.FromLTRB(xMin, yMin, xMax , yMax);
}
finally
{
if (data != null)
source.UnlockBits(data);
}
Bitmap dest = new Bitmap(srcRect.Width, srcRect.Height);
Rectangle destRect = new Rectangle(0, 0, srcRect.Width, srcRect.Height);
using (Graphics graphics = Graphics.FromImage(dest))
{
graphics.DrawImage(source, destRect, srcRect, GraphicsUnit.Pixel);
}
return dest;
}
I'm trying to trim a Bitmap with Text Drawn on it.The Proper Image should look like this after trimming
But after trimming i get the following result ..the bottom portion clipped off
What i'm i doing wrong? Please advice..
This is actually a problem with Rectangle.FromLTRB !
Looking closer at the images you will find that you have actually lost only one row of pixels. (The strong magnification had me fooled for a while..)
The algorithm to determine the Height (and Width) of the rectangle is basically right, but off by one.
If you use this
srcRect = Rectangle.FromLTRB(xMin, yMin, xMax + 1 , yMax + 1);
or this:
srcRect = new Rectangle(xMin, yMin, xMax - xMin + 1 , yMax - yMin + 1);
it should work.
You can test with pen and paper: Say: 1st pixel row with a color = 4, first from bottom on a 10 pixel square: 8, that makes 5 not 4 net data: 4,5,6,7,8.
Do note that this issue is inherent in FromLTRB:
Rectangle myRectangle = Rectangle.FromLTRB(0, 0, 10, 10);
..results in a Rectangle with Height=10 even though 0..10 should cover 11 pixels rows! So the Right-Bottom coordinate is actually excluded from the result!!
I think the whole issue with rectangles being off by one stems from legacy ways to use a Pen with its alignment. When using the same rectangles to fill with a Brush all works as expected.
I have the following code for looping pixels in an image:
Bitmap myBitmap = new Bitmap(pictureBox1.Image);
for (x = 0; x < pictureBox1.Image.Width; x += 1)
{
for (y = 0; y < pictureBox1.Image.Height; y += 1)
{
Color pixelColor = myBitmap.GetPixel(x, y);
aws = pixelColor.GetBrightness();
}
}
The above works. What if i want to exclude an area of the image. The area is an area selected by the user,for example:
from x=200&y=30 to x=250&y=30
from x=200&y=35 to x=250&y=35
from x=200&y=40 to x=250&y=40
from x=200&y=45 to x=250&y=45
How i loop all pixels except the one i wrote above?
Thank you!
I think you can do something like the following
Rectangle rectToExclude = new Rectangle(200, 30, 250, 30);//rectangle to be excluded
Bitmap myBitmap = new Bitmap(pictureBox1.Image);
for (x = 0; x < pictureBox1.Image.Width; x += 1)
{
for (y = 0; y < pictureBox1.Image.Height; y += 1)
{
if (rectToExclude.Contains(x, y)) continue; // if in the exclude rect then continue without doing any effects
Color pixelColor = myBitmap.GetPixel(x, y);
aws = pixelColor.GetBrightness();
}
}
Maybe write a function to test x and y like this:
public static bool IsInArea(int testx, int testy, int x1, int y1, int x2, int y2)
{
if (testx > x1 && testx < x2 && testy > y1 && testy < y2)
{
return true;
}
else
{
return false;
}
}
and then use it like this:
BitmapData bmd = myBitmap.LockBits(new Rectangle(0, 0, myBitmap.Width, myBitmap.Height),
System.Drawing.Imaging.ImageLockMode.ReadWrite,
myBitmap.PixelFormat);
int PixelSize = 4;
unsafe
{
for (int y = 0; y < bmd.Height; y++)
{
byte* row = (byte*)bmd.Scan0 + (y * bmd.Stride);
for (int x = 0; x < bmd.Width; x++)
{
if (!IsInArea(x, y, 200, 30, 250, 30))
{
int b = row[x * PixelSize]; //Blue
int g = row[x * PixelSize + 1]; //Green
int r = row[x * PixelSize + 2]; //Red
int a = row[x * PixelSize + 3]; //Alpha
Color c = Color.FromArgb(a, r, g, b);
float brightness = c.GetBrightness();
}
}
}
}
myBitmap.UnlockBits(bmd);