Get pixels/points marked by draw.line in pygame - pygame

I want to get the pixels/points marked by pygame.draw.line() function in pygame. How can this be achieved?

You could create a surface, and draw the line on the surface.
Then you can loop through the surface to find the pixels that are the same color as the line.
EDIT:
you could also write a function returning the points of a Bresenham's line algorithm.

Related

AS3 - How to calculate intersection between drawing and bitmap

I'm trying to create a handwriting game with AS3 on Adobe Animate. I've created my board, functions(drawing, erasing, saving, printing and color pannel) so far. But i need to show a score. To do it i thought if i can calculate the percentege of intersection between drawing and a bitmap image(which is my background for now).
Is there any way to do it? Or can you at least tell me with which function should i try that? Thanks a lot.
Note: Here is 2 images from my game. You can easily understand what am i trying to explain and do.
players will try to draw correctly(drawn board)
Empty Board
just a suggestion,
lets assuming that you are recording draw data, a set of points according the frame rate that records mouse positions inside an array.
i used 8 points in my own example, the result would be like this: (6 of 8 = 75% passed)
► black line is correct path(trace btimap) ► red is client draw
we need to search whole of the points array and validate them, so a percentage will be gain easily
how to validate
each point contain x and y, to check if its placed on a black pixel (bitmap trace) we just do
if (bitmapData.getPixel(point.x, point.y) == 0x0) // 0x0 is black
getPixel returns an integer that represents an RGB pixel value from a
BitmapData object at a specific point (x, y). The getPixel() method
returns an unmultiplied pixel value. No alpha information is returned.
Improvment
this practice would be more accurate when there is really more captured points during draw, also the Trace-Bitmap must be like this (above image), not a Dashed (smoothed, styled, ...) Line, however you can use this trace bitmap in background (invisible) and only present a dashed copy of that with a colorful background (like grass and rock textures or any graphical improves) to players.
Note
also define a maximum search size if you need more speed for validating draw. this maximum will be used to ignoring some points, for example if max=5 and we have 10 points, 0,2,4,6,8 can be ignored

erase certain circles in pygame window

I have a pygame screen with multiple tree like objects which grows with each update. I also have to draw random circle which appear and disappear with each update.
I am not able to make the circles alone to disappear. If I try to redraw I loose the slowly incrementing tree structure also. Any help
Using sprite groups (http://www.pygame.org/docs/ref/sprite.html#pygame.sprite.Group) you can put all the tree like objects into a sprite group designated for trees. Then at the end of the game loop you could blit the background onto the screen and call "tree_group.draw(screen)" to draw all your tree sprites wherever they may be on the screen. With that in place, you can simply draw a random circle wherever you'd like without worrying about taking corrective measures and trying to fix where the circle was drawn previously. Using sprite groups makes updating in game loops a breeze as well. Just call "tree_group.update(args)" and every object in the group will update with the arguments passed in.

Actionscript: Make a mask follow a line (and "grow")

does anybody know/have some idea how to make a mask follow a line? Basically I have a drawing made with 1px line and I need to gradually mask this shape so it actually looks like it is being drawn. The thing is that I cannot just increase the width of the mask (it would simple draw a vertical line in one step which is not desired), it has to be a linear movement along the "guide" line, so the vertical line gets drawn in several steps. Doing this manually will/would be a major pain. This is what I am trying to achieve:
Thanks a lot!
You have to do it manually. Though there are some shortcuts you can take:
Create a Guide layer in Flash Pro.
Copy a vector of your path to this guide layer.
Create a new layer below it, put a circle on that layer at the start of the path and make a classic tween of that circle.
Dock your circle layer under your guide layer and at the last frame of your tween move the circle to the end of the path. This will make the circle go along the path.
Follow the animation and manually fill the covered parts.
Put your guide, circle animation and following animation into a MovieClip and put it above your to be masked symbol and make its layer a mask.
Here's an example I made for you if I wasn't clear enough: http://db.tt/kvaaYaLA
Note that this method is only useful if you need a static animation, not for a dynamic one.

Output values in Pixel Blender (trace)

I'm absolutely new to Pixel Blender (started a couple of hours ago).
My client wants a classic folding effect for his app, I've shown him some example of folding effect via masks and he didn't like them, so I decide to dive in Pixel Blender to try to write him a custom shader.
Thx God I've found this one and I'm modyfing it by playing with values. But how can I trace / print / echo values from Pixel Blender ToolKit? This would speed up a lot all the tests I'm doing.
Here i've found in the comments that it's not possible, is it true?
Thx a lot
Well, you cannot directly trace values in Pixel Bender, but you can, for example, make a certain bitmap, then apply that filter with requested values and trace reultant bitmap's pixel values to find out what point corresponded the one selected.
For example, you make a 256x256 bitmap, with each point (x,y) having "x" red and "y" green component value. Then you apply that filter with selected values, and either display the result, or respond to clicks and trace underlying color's red and green values, which will give you the exact point on the source bitmap.

draw line in actionscript 3 without using the draw API?

I need to be able to draw a thick patterend line between 2 points in AS3, I can't use the draw API because it doesn't all me to actually put detail (pattern etc) into the thickness of the line, I thought about perhaps using the line to create a bitmap version and then using that as a mask, but I remember many years ago seeing some examples that use a movieclip as a source for a line, but I can't find examples of that now at all, any ideas?
I've attached an example image of how I want the line to look.
I suspect Graphics.lineBitmapStyle() will do the trick. If you want to use a Sprite or MovieClip as the source, you'll have to draw() it to a BitmapData first. The example code on that later link should get you up and running with that.