I have some graphics that is already scaled and cut correctly for my project.
I choose to build the UI in IB and positioned everything correctly, under size and position I left it a "Frame" (instead of layout).
At runtime my graphics is moved and stretched according to which UIViewContentMode I set.
If I was doing this completely in code and set a frame and no UIViewContentMode, Cocoa would respect this and leave the graphics alone. However IB does things a bit different.
I think my problem is that I don't precisely understand what the different UIViewContentMode's does and I can't find the correct one to "turn off" the manipulation of the graphics at runtime.
Can someone give my a little help on this one:)
Thanks in regards.
If you don't set the value, the default is UIViewContentModeScaleToFill. If doing it in code and then calling setNeedsDisplay does it "scale to fill"? I think it depends on how you "do it in code" when the content mode is enforced - I assume IB is doing some extra stuff in the init to apply the content mode that you are not doing in code.
Anyway, if you don't want it to "scale" you can pick any of the UIViewContentMode operations that don't have the word "Scale" in the name. Review the UIViewContentMode enum for details on what each one does.
Related
Being a somewhat proficient iOS developer, I have just started working on a desktop OSX project in Cocoa and I'm running into issues that I just can't grasp. So this question is for the OSX developers out there.
I don't like the Interface Builder much, so I tend to write my views in code. The most prominent method I write my view layout code in is a view controller's loadView method, and at least on iOS I use autoresizingMasks for everything. Try out the view small, large, rotated landscape and portrait and if all is dandy, I continue with the next item on my list. Now on the desktop, the autoresizingMask works (or just looks) a little bit different. First of all the properties have different names, but their behavior also seems weird or unexpected.
When I ran into the issue below, I thought it must be my code was wrong, so after trying out long enough I re-created it with Interface Builder just for confirmation's sake, and guess what: I got the exact same result. Take a view with four vertically stacked subviews. Set the middle two to have flexible heights, the outer ones to be fixed. When you run it, size it down and back up again, I get two completely different layouts before and after the resize. See image:
Now I can follow why this happens from a mathematical standpoint between run loops, but from the point of an 'autosizing' or 'autoresizing' feature, this makes absolutely no sense.
Before I try to write the mother-of-all-resizing-topics here, might I ask you these questions? Feel free to elaborate some more on the resizing topic if you feel it adds to the post.
Am I a fool for not wanting to use the Interface Builder on desktop projects?
Should I depend on the autoresizingMask less than I would on iOS projects?
What are decent alternatives to making sure your layout lives up to standards without Interface Builder?
Cheers!
Yes, in my opinion. :)
You should depend on it when it does what you need. When it's insufficient, override resizeSubviewsWithOldSize: and/or resizeWithOldSuperviewSize: (or see below).
???
If you can target 10.7, look at the new constraint-based layout system. Check out the Cocoa Autolayout video from WWDC 2011.
You could also set minSize on your NSWindow to something large enough to prevent the singularity.
I'm not sure I'd say "fool," but refusing to use Interface Builder on the Mac is a very…avante-garde choice.
You should definitely use autosizing on your views.
Be maniacally attentive and spend lots of time making sure everything is right. (This is why I don't recommend going without Interface Builder. In general, what you get is a lot of wasted time that you could have spent doing something else.)
In this case, I think the best approach would be to set a sensible minimum height for the window. Don't let it get too small to display what it needs to display.
I have some quads that have a texture with transparency and some objects behind these quads. However, these don't seem to be shown. I know it's something about GL_BLEND but I can't manage to make the objects behind show.
I've tried with:
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
but still not working. What I basically have is:
// I paint the object
draw_ac3d_file([actualObject getCurrentObject3d]);
// I paint the quad
paintQuadWithAlphaTexture();
There are two common scenarios that create this situation, and it is difficult to tell which one your program is doing, if either at all.
Draw Order
First, make sure you are drawing your objects in the correct order. You must draw from back-to-front or else the models will not be blended properly.
http://www.opengl.org/wiki/Transparency_Sorting
note as Arne Bergene Fossaa pointed out, front-to-back is the proper way to render objects that are not transparent from a performance stand point. Because of this, most renderers first draw all the models that have no transparency front-to-back, and then they go back and render all models that have transparency back-to-front. This is covered in most 3D-graphic texts out there.
back-to-front
front-to-back
image credit to Geoff Leach at RMIT University
Lighting
The second most common issue is improper use of lighting. Normally in this case if you were using the fixed-function pipeline, people would advise you to simply call glDisable(GL_LIGHTING);
Now this should work (if it is the cause at all) but what if you want lighting? Then you would either have to employ custom shaders or set up proper material settings for the models.
A discussion of using the material properties can be found at http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Number=285889
So I want to have a view (NSView, NSOpenGLView, something CG related?) which basically displays a map. Such as:
http://dump.tanaris4.com/map.png
Obviously that looks horrible, but I did it using an NSView, and it draws SO slow. Clearly not designed for this.
I just need to allow users to click on the individual (x,y) coordinates to make changes, and zoom into a certain area (to see it better).
Should I go the OpenGL route? And if so - any suggestions as to how to get started? (I was able to follow the guide to draw a triangle, so that's good).
I did find this post on zooming in an NSView: How to implement zoom/scale in a Cocoa AppKit-application
My concern is if I'm drawing over 6000 coordinates and the lines connecting them, this isn't efficient at all.
I don't think using OpenGL would be of any good here. The problem does not seem to be the actual painting, but rather the rendering strategy. You would need a scene graph of some kind to dynamically handle level of detail and culling.
Qt has all this packaged in a nice class class QGraphicsScene (see http://doc.qt.nokia.com/latest/qgraphicsscene.html for reference, and http://doc.qt.nokia.com/main-snapshot/demos-chip.html for an example).
Some basic concepts you should consider using:
http://en.wikipedia.org/wiki/Scene_graph
http://en.wikipedia.org/wiki/Quadtree
http://en.wikipedia.org/wiki/Level_of_detail
Try using core graphics for this, really there is so much that could be done. Watch the video Practical Drawing for iOS Developers from WWDC 2011 and it should give an over view of what can be done with CG.
I believe even CoreGraphics will suffice for what you want to achieve, and that should work under a UIView if you draw the rectangle of your view completely under the DrawRect method of your UIView (you must overload this method). Please see the UIView Class Reference. I have a mobile application that logs points on the UIMapKit, kind of like Nike+, and it certainly works well for massive amounts of points/line segments. There is no reason why this simple approach cannot work for you as well.
I want to do some custom drawing in a NSView subclass where should I get started?
As Jarret mentioned the Apple docs are a great place to start. However, some things to bear in mind:
The default coordinate system used with views is the Cartesian coordinate system where the origin is in the bottom left corner of the view. Most often you want the origin to be in the top left corner of the view so this is where you override the isFlipped: method (the default implementation which returns NO), returning YES:
- (BOOL)isFlipped
{
return YES;
}
This "flips" the coordinate system so that the origin becomes in the top left corner, after a vertical flip has taken place. This can make some drawing position calculations easier.
The main things you'll probably want to get started with are things such as:
Filling basic rectangles (using the NSBezierPath class method fillRect:, along with the NSColor class for setting and using colours).
Working with images (using the NSImage class and the drawing methods it provides).
Paths, where you can draw lines and other shapes (with the NSBezierPath class).
You'll also want to take a look into Graphics Contexts at some point, and working with setting attributes (such as the current colour, a shadow etc) on them, used for subsequent drawing operations.
Probably not of immediate concern, but just a side note, that at some point you should take a look at the Optimizing View Drawing section of the View Programming Guide for Cocoa. Drawing operations should be fast, and it amazes me sometimes how little consideration people put into the performance aspects of drawing, when there are some basic things you can do to make your drawing – and therefore application – more efficient, such as only redrawing parts of the view that have actually changed, rather than the entire thing.
Apple's Introduction to Cocoa Drawing Guide is the best place to start. Lots of examples there.
You should start at the beginning.
If i wanted to crop an image in VB.net, how would I go about doing it? I am trying to let the user drag out the box they want (system.drawing.rectangle), and it will automatically remove the edges surrounding the box.
My first problem is primarily the fact that I cannot make the system.drawing.rectangle visible. It is not displaying at all, I am setting its location and height programmatically, but nothing is showing up. I know there is probably something fairly obvious I am missing...but I cannot seem to find it.
My larger issue, however, lies with the cropping itself. I cannot find any crop methods, at all. Is there a hidden one I am missing? Or must I code it myself? How would I go about doing this? It ought to be able to output to a bitmap image object.
Thanks for the help, I am surprised this hasn't been asked on here before....
Regarding your first problem: a Rectangle isn't by itself visible. You have to draw it on your canvas using the Graphics object's DrawRectangle(...) method. For drawing a selection tool, you'll want to set your Pen object's DashCap and DashPattern properties.
To "crop" an image, you basically want to take the portion of a larger image delineated by a smaller Rectangle, and turn it into a new Bitmap. This can be done using one of the 30 overloads of the Graphics object's DrawImage(...) method. You can either keep the cropped portion in its original dimensions (resulting in a smaller Bitmap than your original), or you can "blow it up" to something like the original image's size. If you do the latter approach, it is usually a good idea to set your Graphics object's InterpolationMode property to HighQualityBicubic (I think that's the one, anyway), since the default InterpolationMode is pretty crappy.
There are a number of different ways of rendering images in .Net - it might help if you posted some of your code, along with an explanation of the exact problems you're running into.
Here is another answer with a link to a sample app (and source code in C#, sorry) that may help you get started.
There are a number of articles on these topics on CodeProject:
Pick your favorite flavor (though I encourage you to check out the C# projects - it shouldn't be too hard to convert).
VB
Image Cropping with Image Resizing Using vb.net
C#
Cropping Images
An Easy to Use Image Resizing and Cropping Control
Image Processing using C# (see the Cropping section - I was able to use this code in one of my projects)
WPF/C#
WPF Interactive Image Cropping Control
A Photoshop-like Cropping Adorner for WPF