Visual representation of the Point array (zoom to 800%): http://i.cubeupload.com/2Y3JPf.png
Please do not reupload to Imgur. Imgur's compression makes the image too blurry at high zooms.
(a zoomed in part of the image with the relevant dots highlighted:)
In the image, each red dot represents a Point. All the red dots combined represent the Point array. FYI, the Point array is ordered left to right, top to bottom. So pointArray[0] is in the top-left, pointArray[1] is in the top right, pointArray[2] is in the top-left but is also one line below pointArray[0] and pointArray[1].
As you can see, the majority of the red dots are in a grid but there are a couple of outliers in the top-left of the window and in the bottom-right where the number of mines are displayed. How would I get rid of the outliers? I've thought of parsing each point one by one to see if they are a constant number of pixels away from each other but at which point do I start? pointArray[0] is in the top-left so it's not even part of the grid which would mean that finding a constant pixel gap isn't going to work.
Any ideas?
Here is a method that should work for all grid sizes:
Count the number of dots in each row, and the number of dots in each column.
Then remove all dots in rows and columns that have less than the average number of dots.
You can construct such a histogram efficiently with a dictionary:
var numDotsPerRow = new Dictionary<int,int>();
var numDotsPerColumn = new Dictionary<int,int>();
foreach (var point in pointArray)
{
int count;
numDotsPerRow.TryGetValue(point.X, out count);
numDotsPerRow[point.X] = count+1;
numDotsPerColumn.TryGetValue(point.Y, out count);
numDotsPerColumn[point.Y] = count+1;
}
Related
I'm working to a software that need a strange feature. I choose a png image like image attached and I need to place uniformly a certain number of points on black surface. I started with loop each pixel and change it's color to black, only for design, but now I need to think an algorithm to fill it with points (like 200 points (pixels with red color). You have a idea how to do this ?
Now in my mind is to count black pixels, then do something like this blackPixelsPerPoint = blackPixels / numberOfPoints. After this I now i need to have a red point every blackPixelsPerPoint.
The result need to be something like N letter
The points need to have almost same space between them and fill all the black surface if is possible (depend by number of points).
Does anybody now how to prevent the Y-axis from moving (horizontally) when the text area increases (for example when displaying 100 instead of 1 on a label on the Y-axis).
The following image illustrates the problem; when a decimal is added to the number on the labels, the diagram is resized and the Y-axis is moved to the right:
The reason the Axis and other a few other ChartElements may move is that their Positions are set to Automatic by default; so when the lables need more space they get it and the inner portion is reduced.
So if you want to prevent that you need to set an explicit values for the X values of its Position.
Note that the values are in percent of the respective containers.
Unless you set a special Crossing value, the primary axes are always drawn to the left and bottom of the InnerPlotArea.
So you want to set the position, maybe like this:
ChartArea ca = chart1.ChartAreas[0];
ca.InnerPlotPosition.X = 10;
Note however, that this means: The Y-Axis will start at 10% of the whole ChartArea.Width, which usually means something like 'almost 10%' of the whole Chart.Width. (The Legend and some white space will usually take some space, too).
So if you resize your chart the axis may sit a little too much to the right.. You may want ot play with the number and maybe code an extra line in the Resize event of the Chart.
I have a Region, from which I am subtracting n number of Rectangles, now I need to get all the remaining space in terms of rectangles. Is there a way of doing it?
Thanks
First you should realize that any set of rectangles you get may be an approximation if the region contains any curves.
Second, try calling GetRegionScans with an indentity matrix.
RectangleF[] rects = region.GetRegionScans(new Matrix());
As part of my self-education of programming I decided to make a snake in C#. The problem I have is about the client size of the game form.
I want player to be able to scale the window of the game, which is divided into 25 x 25 grid (every coordinate is like "one pixel") - it means, that at any moment, the window is divided into 25 x 25 identical squares.
The problem I get is near this code:
int SquareSide = (ClientSize.Width / 25);
When I set the ClientSize strictly to for example 600 x 600, which is a multiple of 25, everything goes OK. But when I don't (for example by manual resizing, which can change the size to, for example, 711 x 711), it creates at the right side a 'strip', which seems to be the rest of pixels, which can't be used because we are dividing to integer number.
My question is - is there any not-extremely-hard way to achieve dividing ANY client size of form into 25 x 25 grid without this problem? I tried using double, but FillRectangle method doesn't accept it.
I hope my question is understandable and thank you for replies.
To tell you the truth, there is
g.FillRectangle(Brush b, RectangleF rect)
RectangleF is a rectangle whose coordinates are float.
So you can use:
float SquareSide = (ClientSize.Width * 1f / 25);
I would try to simply handle OnResize event of the window, and at the moment user finishes rezise it, force the size that program need for perfect fit of the grid.
So for example at the moment user releases mouse and you figure out that one dimensions of the window 711x711, bring it to nearest correct fit 700x700.
In this way you guarantee good user experience on different monitor resolutions and for you guarantee a correct fit of the grid you draw.
Hope this helps.
Switch to float coordinates for everything. Make sure your game looks OK when lines do not have whole pixel coordinates. Make sure you "find next cell" code also works with floats, including mouse position detection if needed.
The other approach is to be happy with integer coordinates (and cells of the same size) and make page layout flexible to accomodate some unused space for odd 711x711 layouts (i.e. just center the field and keep some variable width border).
So I'm building a custom control in C# (not WPF), and I basically want to implement text highlighting with the mouse.
How do I efficiently find the character at a given Point (say where the mouse is clicked) in a string? I have the layout rectangle of the string as it was drawn and I could calculate the length of the string up to every character until I find the one closest to where the mouse is clicked... but there has to be a better way. Any suggestions?
If I had to do this, I would look at it backward.
I'd keep the text entered as a string member in the control, so at all times I know what is actually entered in the control (like the Text property in a TextBox).
Then I would use the TextRenderer.MeasureText() method (http://msdn.microsoft.com/en-us/library/7sy6awsb.aspx) and I would keep measuring the length of the string repeatedly until I pass the X coordinate of the mouse within the control, right then I know how many characters are chosen.
For example, assume the user has the text Hello written in the control.
And the X coordinate hit right between the l and the o, which could be of value 20.
Then I would repeatedly calling MeasureText() on the following strings:
H: width of 5 pixels.
He: width of 10 pixels.
Hel: width of 14 pixels.
Hell: width of 17 pixels.
Hello: width of 22 pixels.
Then I know the mouse was hit between the l and the o, so I would then highlight the text Hell.
Sorry for the distasteful example =)
UPDATE:
You can optimize this a bit by calculating the lengths in a binary-search-tree-like fashion.
Just like you would look up a name in the phonebook, you don't look page by page, but rather split in half as you go along, getting closer and closer until it's definitely between these two pages.
Similarly, especially for long string values of the control, calculate the width of the entire string, then half its length, and split there. I think that would be O(n log n) at that point.
Of course it would be O(1) if the text is of fixed width =)
Another thing you can do to build upon BeemerGuy's great suggestion is to precalculate an array of offsets. As the string is changed (the user types or the property is set in code) you can recalculate the offset array. That will save you the call to MeasureFont on the mouse clicks and will make finding the character trivial. You basically iterate the array until you find the nearest character. Since the offsets are implicitly sorted by value you can even use a binary search to make it more effective.