I have a large image background with several areas or objects in the images which can be clicked and an event is triggered. The method I'm currently using to accomplish this is by slicing the images of objects and area and positioning them over the background image and assigning a click handler to them.
This works for the moment but I feel that there should be a better way of doing this. One way I thought and tried is to fill the sliced images with black or white, position them over the background image, make their opacity 0, make them hit testable and assign a click handler.
Does this method have advantage over the previous one? Does making an image object transparent use less texture memory or is it the same?
And are there other better ways to do so? My main objective is about making the game use less texture memory and cutting the overall project file size by using less of those sliced images.
Use display.newRect/newCircle to mark down area, make them transparent and hit testable.
This should be more efficient than using images.
Related
I have a large image, based on a vector drawable xml file, and I would like to visualize only part of it in an ImageView, like this (the darker regions would be off screen):
Under user control, the image would move around (or rather, the visible part of it), very much like a Google maps app.
I can manage to dig into Android Studio but I would like to get some hint on what would be a proper approach to handle this. Is using a large xml file and clipping it appropriate or is it better drawing it on a canvas in runtime?
I played with both vector drawables and drawing on a canvas, but not enough to be sure which way to go for this or to post any code.
I want to know if it's possible to use gradient colors in the launchscreen.storyboards if so where can I edit it. I'm not looking to add images because it can make the app to heavy but maybe a transition to change the gradient from a-colors to b-colors.
thanks in advance.
If you want to render gradients programmatically in a storyboard, you can generally define a UIView subclass to do that, but you cannot use custom classes in the launch screen. You’ll have to use an image.
If your gradient is a simple vertical or horizontal gradient, and you’re really concerned about asset size, you can define a very narrow image and then add an image view with “scale to fill” content mode.
But these images are so small anyway, the amount of space saved will be negligible, so I’m not sure it’s worth worrying about.
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 have been looking for the solution on the web for a long time. Most tutorials are fairly simple about adding shadow to a UIView. I also noticed that if we add a shadow to an UIImageView. The shadow shape could perfectly fit the shape of the content image if the image itself has alpha channel in it. Say for example, if the image is an animal with transparent background, the shadow shape is also the same as that animal (not a rectangle shadow as same as UIImageView frame).
But these are not enough. What I need to do is to add some changes to the shadow so it may have some rotation angle and compressed (squeezed or shift) effect so that looks like the sunlight comes from a certain spot.
To demonstrate what I need, I upload 2 images below, which I captured from the Google Map App created by Apple. You can imagine the Annotation Pin is an image which has the Pin shape, so the shadow is also "pin shaped", but it is not simply "offset" with a CGSize, you can see the top of the shadow is shifted right about 35 degrees and slightly squeezed the height.
When we tap and hold and pin, the shadow is also animated away from the pin, so I believe that such shadow can be made programmably.
The best shadow tutorial I can found so far is http://nachbaur.com/blog/fun-shadow-effects-using-custom-calayer-shadowpaths But unfortunately, that cannot make this effect.
If anyone know the answer or know any better words to search for, please let me know. Thank you.
(Please note that the shape of the image is dynamic in the App, so using any tool like Photoshop to pre-render the shadow is not an option.)
In order to create dynamic effects like this, you have to use Core Graphics. It's incredibly powerful once you know how to use it. Basically you need to set a skew transform on the context, set up a shadow and draw the image. You will probably have to use transparency layers as well.
It doesn't sound like you can use CALayer shadows, since that is meant to solve a specific use-case. The approach Apple takes with the pin marks on the map is to have two separate images that are created ahead of time (e.g. in Photoshop) and they position them within the map relative to a reference point.
If you really do need to do this at run-time, it should still be possible by using either Core Graphics or ImageKit. To get a blurred shadow appearance, you can use the kCICategoryBlur CIFilter. You can then convert the image to grayscale. And to get that compressed look you just need to resize and skew the image.
Once you have two separate images, you can either take the CGImageRef for the shadow image and can set that as the content of another sublayer, or you can add it as a separate view.
If you know what all the shapes are, you could just render a shadow image in Photoshop or something.
I am a coder but not a graphic maker. I can decently produce graphics that meet the quality standards visually although I cannot produce graphics that will technically "work." This is what I mean:
I am using CGRectIntersectsRect for colliding images. My image has SOME extra space which I have made completely transparent using Adobe PhotoShop but even if this extra transparent space is not visible, when the two images collide, it will look like you will be hitting nothing as this extra invisible transparent space is PART of the image and when CGRectIntersectsRect is called it detects touch between two images. So if the other image touches the transparent space, CGRectIntersectsRect is called and my code is executed. I only want my code to be executed if it hits the actual COLOR space of the image. Here is two things that could help me through that, they follow through with questions.
Learn how to make NO EXTRA SPACE on an image in photoshop. How could I do this, tutorials?
CGRectIntersectsRect only called when touching a color part of an image. A way to do this?
Thank you guys!
Regarding your question #1, it depends. All images are rectangular, all. So, if your sprite is rectangular, you can crop it in Photoshop to just the rectangular area. But if you want to handle, say, a circle ball, then you can't do such thing as "remove extra space". Your circle ball will always be stored in a rectangular image, with transparent space on the corners.
Learn how to make NO EXTRA SPACE on an image in photoshop. How could I do this, tutorials?
You can manually select an area using the Rectangular Marquee Tool and Image > Crop or automatically trim the image based on an edge pixel color using Image > Trim.
CGRectIntersectsRect only called when touching a color part of an image. A way to do this?
You can use pixel-perfect collisions or create better bounding shapes for your game objects. For example, instead of using pixel-perfect collision for a spaceship like this one, you could use a triangle for the wings, a rectangle for the body, and a triangle for the head.
Pixel-perfect collision
One way you could implement it would be to
Have an blank image in memory.
Draw visible pixels from one image in blue (#0000ff).
Draw visible pixels from the other image in red (#ff0000).
If there's any purple pixels in the image (#ff00ff), then there's an intersection.
Alternative collision detection solution
If your game is physics-based, then you can use a physics engine like Box2D. You can use circles, rectangles, and polygons to represent all of your game objects and it'll give you accurate results without unnecessary overhead.
For collision detection for non-rectangular shapes, you should look into one of the many game and/or physics libraries available for iOS. Cocos2d coupled with Box2d or chipmunk are popular choices.
If you want to do it yourself, you'll need to start with something like a custom CGPath tracing the actual shape of each object, then use a function like CGPathContainsPoint (that's from memory, it may be wrong). But it is not a simple job. Angry birds uses box2d, AFAIK.