I am trying to draw arrows. I know how to draw lines which takes me half way there but I want the tip to have a small triangle just like an arrow. However even when I use a triangle as a point, obviously it does not always point towards the direction of the line and might sometimes produce weird looking arrows.
I would like to draw the passes a player makes on a soccer field. I do that using LINESTRING and 4 coordinates I have in a table in my database. I use the xFrom, yFrom, xTo and yTo coordinates and I manage to draw lines. However I would like to have the tip of the line to show as an arrow but I found nothing in Google or in SQL documentation.
I would like to use SSRS and not any other graphics vector program because its simpler and its incorporated easily in my overall report.
Anyone can suggest a way of turning a line into an arrow?
Thanks
Okay, first off I'd like to preface this answer with the statement that using SQL Server and Reporting Services as a graphics tool is asking for trouble. This is by far, not what it was meant for.
With that being said, I believe this would work. You will need to spend some time studying, though. When manipulating images, you have several operations that you can perform. (Like Rotating, skewing, resizing, etc.) The mathematics behind these operations can be performed using matrix algebra. What you will need to do is look at the line you have created. It has a slope. If you picture that line superimposed upon X and Y axes, you can see that there is an angle between the line and the Y axis. (Assumes that the triagle's base rests upon the X axis.) That angle is the angle that you will want to rotate your triangle that you're using as the tip of the arrow. That should fix your problem. You could create a formula to do the calculations. (If the formula engine is robust enough to handle matrix algebra.)
Here are a couple of pages that give you the basics of how to rotate an image.
http://datagenetics.com/blog/august32013/index.html
http://www.fastgraph.com/makegames/3drotation/
Good luck!
Related
I am attempting to come up with a quick and efficient means of translating a 3d mesh into a projected AABB. In the end, I would like to accomplish something similar to figure 1 wherein only the area of the screen covered by the cube is located inside the bounding box highlighted in red. ((if it is at all possible, getting the area as small as possible, highlighted in blue, would increase efficiency down the road.))
Figure 1. https://i.imgur.com/pd0E20C.png
Currently, I have tried:
Calculating the point position on the screen using camera.unproject_position(). this failed largely due to my inability to wrap my head around the pixel positions trending towards infinity. I understand it has something to do with Tan, but frankly, it is too late for my brain to function anymore.
Getting the area of collision between the view frustum and the AABB of the mesh instance. This method seems convoluted, and to get it in a usable format I would need to project the result into 2d coordinates again.
Using the MeshInstance VisualInstance to create a texture wherein a pixel is white if it contains the mesh instance, and black otherwise. Visual instances in general just baffle me, and I did not think it would be efficient to have another viewport just to output this texture.
What I am looking for:
An output that can be passed to a shader informing where to complete certain calculations. Right now this is set up to use a bounding box, but it could easily be rewritten to also use a texture. It also could be rewritten to use polygons, but I am trying to keep calculations to a minimum in the shader.
Certain solutions I have tried before have worked, slightly, but this must be robust. The camera interfacing with the 3d object will be able to move completely around and through it, meaning at times the view will be completely surrounded by the 3d model with points both in front, and behind.
Thank you for any help you can provide.
I will try my best to update this post with information if needed.
So I have my game, made with SpriteKit and Obj-C. I want to know a couple things.
1) What is the best way to make scroll-views in SpriteKit?
2) How do I get this special kind of scroll-view to work?
The kind of scroll-view I'd like to use is one that, without prior knowledge, seems like it could be pretty complicated. You're scrolling through the objects in it, and when they get close to the center of the screen, they get larger. When they're being scrolled away from the center of the screen, they get smaller and smaller until, when their limit is met, they stop minimizing. That limitation goes for getting bigger when getting closer to the center of the screen, too.
Also, I should probably note that I have tried a few different solutions for cheap remakes of scroll views, like merely adding the objects to a SKNode and moving the SKNode's position relative to the finger's, and its movement . . . but that is not what I want. Now, if there is no real way to add a scroll-view to my game, this is what I'm asking. Will I simply have to do some sort of formula? Make the images bigger when they get closer to a certain spot, and maybe run that formula each time -touchesMoved is called? If so, what sort of formula would that be? Some complicated Math equation subtracting the node's position from the center of the screen, and sizing it accordingly? Something like that? If that's the case, will you please give me some smart Math formula to do that, and give it to me in code (possibly a full-out function) format?
If ALL else fails, and there is no good way to do this, what would some other way be?
It is possible to use UIScrollViews with your SpriteKit scenes, but there's a bit of a workaround involved there. My recommendation is to take a look at this github project, that is what I based my UIScrollView off of in my own projects. From the looks of it, most of the stuff you'd want has actually been converted to Swift now, rather than Objective-C when I first looked at the project, so I don't know how that'll fare with you.
The project linked above would result in your SKScene being larger than the screen (I assume that is why it would need to be scrolled), so determining what is and is not close to the center of the scene won't be difficult. One thing you can do is use the update loop in SpriteKit to constantly update the size of Sprites (Perhaps just those on-screen) based on their distance from a fixed, known center point. For instance, if you have a screen of width and height 10, then the midpoint would be x,y = 5,5. You could then say that size = 1.0 - (2 * distance_from_midpoint). Given you are at the midpoint, the size will be 1.0 (1.0 - (2 * 0)), the farther away you get, the smaller your scale will be. This is a crude example that does not account for a max or min fixed size, and so you will need to work with it.
Good luck with your project.
Edit:
Alright, I'll go a bit out of my way here and help you out with the equation, although mine still isn't perfect.
Now, this doesn't really give you a minimum scale, but it will give you a maximum one (Basically at the midpoint). This equation here does have some flaws though. For one, you might use this to find the x and y scale of your objects based on their distance from a midpoint. However, you don't really want two different components to your scale. What if your Sprite is right next to the x midpoint, and the x_scale spits out 0.95? Well, that's almost full-sized. But if it is far away from the midpoint on the y axis, and it gives you a y scale of, say 0.20, then you have a problem.
To solve that, I just take the magnitude or hypotenuse of the vector between the current coordinate and the coordinate of the current sprite. That hypotenuse gives me an number that represents the true distance, which eliminates the problem with clashing scale values.
I've made an example of how to calculate this inside Google's Go-Playground, so you can run the code and see what different scales you get based on what coordinate you plug in. Also, the equation used in there is slightly modified, It's basically the same thing as above but without the maxscale - part of the front part of the equation.
Hope this helps out!
Embedding Attempt:
see this code in play.golang.org
I am working on a corporate-level summary report for my employer. Because this is a fairly high-level report, I'm trying to "pretty" it up a bit (I think the standard SAS output is exceptionally ugly). I've managed to include graphics using ODS REGION and the like, but I'm having trouble generating a fairly basic bar chart.
All I want to do is draw boxes onto the PDF file by specifiying X,Y and W,H and the background color. I've gotten close using this SUGI paper (which employs ODS REGION with a PROC GSLIDE).
That works OK, but I've run into many vexing little issues. For example:
There's a minimum height and width for GSLIDE (appx 3 points) which has made it very difficult to represent small numbers on my bar graph
The corners of GSLIDE are slightly rounded, causing strange looking "artifacts" when attempting to overlay and stack them
There's apparently a "maximum" width (appx 480 points). I think I might be able to solve this with the GOPTIONS VSIZE attribute, but I have to be careful because if the ODS REGION and GSLIDE are exactly the same size, then SAS (for some reason) thinks that the GSLIDE is bigger than the REGION and fails to render GSLIDE properly.
I've searched the internet for an easier approach, but it seems there are few SAS programmers trying to do what I'm doing. I know that I'm reinventing the wheel a bit in that SAS providers bar charts via SAS/GRAPH, but they don't provide the level of customization I need to display the results the way I want them.
How can I draw a simple rectangular shape, with nice square corners, and no weird width/height limitations, on a PDF file?
This isn't direclty relevant to the question, but since it's been brought up, here's an idea of what the bar chart looks like:
Each row measures a metric across a mutually exclusive sub-section of a larger population. The Gray bar represents the total size of the population being measured. The blue bar measures the metric (and the reported number is the metric across the sub-section). The "white bar" is the size of the total population. (The light blue bar is an alternate metric displayed only for those who are curious - it will always be smaller than the blue bar.) Some sub-sections contain no data, so they are displayed as "N/A".
There's also a rolling total. So, after one or a few sub-sections are reported, they are rolled into the rolling total. The gray background groups the related sub-sections, with the rolling total reported at the bottom.
This is pretty much exactly what I want this chart to look like. If it can be done using standard SAS charts, I'd be happy to use them - but I think it's been easier to get this effect on my own by painting the graph myself.
I found a partial answer... you can use a LayoutRegion defined via PROC TEMPLATE to set the background color of an ODS REGION. You still must "put something" within the region to force SAS to render it (for example, ODS TEXT = " ";), but it removes at least one pain point: minimum and maximum sizes.
Unfortunately, the corners are still rounded, but I'll update this answer if I can figure out a way to fix that via an attribute or something.
I have some lines that are connected at various points. I want to draw the outline of these lines and I also want to deal with the extra lines at the connection points.
I have seen two similar questions in this website: Here and here
I have handled the normal cases by offsetting the Centerlines and then changing the start and end points of the lines.
but I haven't been able to deal with special cases when the points are near each other.
Unfortunately, my reputation is low I couldn't post images to explain this better.
I'm coding in Visual Basic .net and I'm writing for Autocad, but any advice will be very useful to me.
most problem cases are solved by translation vectors intersection check
black is the original line/curve whatever ...
gray is translation vector (normal to black and size = outline distance)
blue is outline
if the translation vectors not intersect then it is most likely all OK but if they do then just do something like this:
cut off these points from outline
or create some singular point from these intersections
it is more tricky but can avoid some problem cases from bullet #1
Also sometimes help if there is bigger density of control points
Hope it helps a little...
I need to paint the line which links two points.
I am doing it, in Java. I receive two points as parameters and I have to calculate if the straight line between them, is inside the black figure.
I developed my own solution using the straight line equation, but my results are different than using the "professional" programs (such as GIMP or even MS Paint).
Here is a example of what I want:
alt text http://img411.imageshack.us/img411/788/img1q.png
But my algorithm does this:
alt text http://img267.imageshack.us/img267/1908/img2d.png
*The green point is out of the figure and this is not possible.
Any ideas? Anyone know which code is been using for this, in "professional" apps?
Thanks!
Daniel.
EDIT: Images
It looks like you are truncating instead of rounding to the nearest pixel. Difficult to see on those small black ink splotches. Could you post the code?
"Professional" programs most likely use Bresenham's line algorithm.
Look at Bresenham's line drawing algorithm
Straignt lines are drawn using Bresenham's algorithm usually. I didn't get your point about green point being out of the figure - there's clipping to not waste time drawing outside the visible area.