I want to know if my display (or some window) contains a picture.
I think to do the following:
take a snapshot from a display.
scan this snapshot to see if it contains my picture.
How can I scan a picture in an Objective-C Cocoa app?
I suggest to scan your picture first with some rudamentary feature detection. You can blur it and find big opaque regions. Then you can do the same with the captured screen. This way you can find the "center of gravity" of your picture on the screen. Then you can do bit-by-bit comparasm with a small trashold to finetune the position.
When you have the exact position you can do a last step, a bit-by-bit comparsion for the whole picture area to be sure that your picture is fully displayed (no parts are blocked out by other windows) if this is interesting for you.
Related
My problem is three-fold. I'm going to try to explain as detailed as I can, because I've asked this question before and haven't gotten any clear answers.
What I'm Trying to Do:
I have diagonally shaped images, that I'm trying to make clickable, so I separated them out of the background image. They were originally one image, but I've cut out several pieces of the image and I want to align them identically to how they were in the original image. This might not the best method for what I am trying to achieve, and if there is a better way to make non-square areas of an image clickable, that would solve all of these problems. If not, here is my problem. The problem is, as soon as I align them in XML, I boot them up on an Android emulator or my phone, and they are aligned differently on both, differently than the preview and from each other.
Below is my example, and I'll try to explain what I mean.
The black and white grid is my background. The brown, red, and yellow lines are separate images. I don't want to just combine them with the background, because I need those lines to be clickable. I'd set a button behind them, but they are diagonally shaped and I need the entire shape to be clickable. However, they have to be EXACTLY where they are in the background, aligned specifically as they are to the background. The problem is, as soon as I load it on another device, it scales, and everything misaligns.
It also misaligns depending the device, so I presume it's because it's scaling the different parts differently.
I need a way to align it the way I want it, and have each image scale together.
How I've Been Trying This So Far:
Initially, I tried just using XML. And herein was my first problem. My background image is 1920x1080. It loads on the emulator without a problem. However, if I try to load it on my phone, I get the following error:
OpenGLRenderer: Bitmap too large to be uploaded into a texture (5760x3240, max=4096x4096)
So that leads to my first question. Why is my 1920x1080 trying to load as 5760x3240?!
I bypassed this, by using Picasso to scale the image to 1920x1080. As a sidenote, in addition to programmatically loading the image, I also am removing the title bar. Here is my OnCreate:
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main_layout);
Picasso.with(this).load(R.drawable.backgroundimage).resize(1920,1080).into((ImageView)findViewById(R.id.background));
On the XML side, I've tried all sorts of different things. Relative layouts, linear layouts, frame layouts...None seem to scale the separate imageviews the same.
Which leads to my second question.
How do I scale two differently sized imageviews together, so that they maintain their alignment on different sized devices?
My second imageview is 198x547(this would be the equivalent of one of the squiggly lines in the example images) and even setting that in Picasso does not maintain my alignment. In fact, that doesn't seem to work at all, since I have to scale it differently to even match the alignment I have in the original image.
Summary Questions
I need a diagonally shaped portion of an image to be clickable. Is cutting the shape out as a separate image the appropriate method for doing so? If not, how do I make such a specific, non-square area of an image clickable?
I need specific alignments to scale together. Why aren't they?
Why does my png file upscale itself?
I just want to know a simple complement to the code [img] to get it to be shown at a X% of its original size.
I was thinking about [img width="50%" height="50%"] but that doesn't make any sense. Instead of a huge code, what could I place in the brackets to show the image at a X% scale?
Is that a PHP code?
And the other question. I've seen a little "tag" you could place in the direct link that could load an image into its full resolution or a lower size. I tried to find on the web, but I don't know how to describe being specific in my search criteria. For example, I pasted something like http://example.com/image.jpg=fullscreen and the image would load on the entire screen instead of clicking over it to zoom in. Or could it be http://example.com/image.jpg=half to show in half resolution.
I'm creating a simple 2D racing game in Unity. The game has another subwindow that displays the enemy's view. Kinda like a small screen on top; that lets you know where your enemy is or what he's doing.
Currently, I'm using a secondary camera to follow the enemy and a render texture to limit the display of the subwindow as well as its size.
However, I want the size of the window to be flexible like if i want the ratio of the window to be 4:3 instead of a perfect square. With my current implementation, whenever I rescale the subwindow, it just rescales everything up including the view being displayed. What I want to happen is, when I rescale the subwindow, the area being displayed should just be wider. It should just cover more area because I made the window wider. I want the view to be independent.
Is there a way to do this with my current implementation? If not, how can I achieve what I want?
I'm new to Unity so I really hope someone could teach me. Thank you so much.
The are viewed is independant of the size of your window, if you want to change how much is displayed instead of just re fitting the same content in another size you'll have to work with the field of view http://docs.unity3d.com/ScriptReference/Camera-fieldOfView.html
I have a very simple Mac Application; the best way to think of it is a master/detail view. Once an item is chosen on the left-hand side, information appears on the right pane, along with an image (can be various sizes/formats/resolutions due to the source). The user can very quickly select items on the left, and while the detail text on the right-hand pane appears quickly, we notice an immediate lag or plain failure to display the image on the right. Even the largest of images is a few MB, and typically less than 1024x1024 pixels. If the user moves slowly, everything is kosher...but if you go quick, it will hiccup...lag behind a few selections, or not display at all.
I've attempted solutions using nsviews' setNeedsDisplay, and alternatively using Core Animation layers, but nothing seems to do the trick. Is there a guide or set of tutorials on performant image display routines?
Targeting 10.6+
I am working on drag and drop activity for iPad. I have a rectangle PNG image (see the image named as obj2). When I drag obj1 only on the black portion of the rectangle then it should react.
if (CGRectIntersectsRect(obj1.frame, obj2.frame))
{
NSLog(#" hit test done!! ");
}
Right now, this piece of code takes hit test even on the transparent area. How to prevent that to happen?
For something as simple as your specific example (triangle and circle), the link that David Rönnqvist gives is very useful. You should definitely look at it to see some available tools. But for the general case, the best bet is clipping, drawing, and searching.
For some background, see Clipping a CGRRect to a CGPath.
First, create an alpha-only bitmap image. This is explained in the above link.
Next, clip your context to one of your images using CGContextClipToMask().
Now, draw your other image onto the context.
Finally, search the bitmap data for any colored pixels (see the above link for example code).
If any of the pixels colored, then there is some overlap.
Another, similar approach (which might actually be faster), is to draw each image into its own alpha-only CGBitmapContext. Then walk the pixels in each context and see if they ever are both >128 at the same time.