I have a line limit with a label. I would like to replace that label with an image. I realize the ios-charts library can't do that directly but was looking for some insight on how to do this.
There are several ways to do so:
Add the image outside of the ios-charts system, you can calculate the position of the image, and add it there;
You can subclass the ChartLimitLine, add a new property called UIImage, and then you can use it. You may subclass the chart view as a child chart view, and you can add your child limit line there, and then add the image to the view.
If the image is not complicated, such as simple lines and dots, you can choose to manually draw the shape using CoreGrahpics.
It's quite flexible for you to choose a proper way to do that. Just remeber you only need the origin point and the size, then you can add your image wherever you want.
Doing customization requires you understanding OOP and ios-charts in depth.
Related
So, i am new to xcode and iOS7 and i'm trying to create simple container with two elements inside.
I prefer to make it 100% programmatically. (no IB)
I want to create container with two elements Image and Label.
I want to achieve variable width depends on the text element inside.
Here is example:
Based on user action i want to change text on the fly. Let's assume longer text, and main container have to change width too.
And now the question is: What is best approach to to that?
UIView with subviews or something else i'm just expecting direction.
Code examples with be gratefully appreciated.
Thank you in advance.
What you have described is exactly what a UIButton does automatically: it is a container containing an image and a title (text) and it resizes itself automatically when the text changes.
Let us assume, however, that you want to do this yourself. That is, let's say you want a UIView ("container") containing two other UIViews (subviews). Then we need to discuss this requirement:
Based on user action i want to change text on the fly. Let's assume longer text, and main container have to change width too.
This is not going to happen automatically. You can use constraints (auto layout) to describe the size / position of the subviews in relation to the superview, but it works the other way: the superview changes, and the subviews obey. So you will have to change the superview size manually after you change the text.
You can still use auto layout to help you. Let's say the text is in a UILabel. Well, a UILabel wants to change width automatically when the text changes. So far so good. But you must still change the container view width yourself. You can call systemLayoutSizeFittingSize: to learn what the size of the container should be, using constraints, working from the inside out; but then you will have to change its size yourself to that size.
(You can easily create the view, the subviews, and the auto layout constraints in code.)
If you don't want to use autolayout, then you will just calculate the sizes and positions of everything when the text changes and adjust it all yourself (in code). You can learn the size the label needs to be, to fit its text, by calling sizeThatFits: (or sizeToFit which will actually resize it correctly).
I want to place a series of images in a UIView... I want to be able to change each image's color using three different .png files (red,yellow,green) as a status indicator. Other than actually drawing the rectangle and filling it, is there an easier way?
Research effort: I have Googled and looked through SO and found nothing dealing with this.
There are lots of ways you can do this. I think the easiest way would be to pragmatically add UIViews as subviews to your main view, or to your parent UIView.
You can set the frame of your views as well as the background color. See this link
adding uiview as a subview to the main view
You can also use images, but since it is a plain solid color, its a lot of extra storage space, etc. to use images when you can programatically render a color.
If it is a series of rectangles, you can store UIViews in some kind of data structure so it is easier to dynamically change the color at runtime. If you aren't moving them around, then init there frames/geometry so they are in the correct location, then access them as members of an array or something similar.
If you want to add gradients to images, this is the best thing I have found:
Gradients on UIView and UILabels On iPhone
I figured it out... I took a UIButton, changed the Type to "Custom", sized it (32 x 32) and programmatically changed the the image depending on circumstances.
[button setImage:<#(UIImage *)#> forState:<#(UIControlState)#>]
Thanks to both of you for getting the thought process running... :D
Is there a way, without having to create images of my own, to make rounded rectangle buttons look more appealing? For example, providing them with shading, or making them look three dimensional.
Have a look at this article I wrote recently: UI Polish In An Instant
It talks about using layer properties to add visual interest to your UI with relative ease.
If you want to do so, then consider creating a UIView with all your customizations enabling it for user interaction. It might help!
Using Core Animation functions you can make them a bit more exciting. First import the QuartzCore library. Then you can access properties of the view.layer.
button.layer.cornerRadius changes the rounded corners
button.layer.strokeWidth changes the border thickness
button.layer.strokeColor changes the border colour
button.layer.shadowColor use this and other shadow properties to add a nice soft drop shadow
There's a whole bunch of properties you can tweak if you check the CALayer documentation, and these work for any UIView or subclass, not just buttons.
To add a gradient, check out the CAGradientLayer. You can create one of these and append it as a sublayer to your button.layer.
There's also CAShapeLayer to add an arbitrary polytonal shape to your button, all drawn using code without any images.
There is a UIScrollView and I'd like to programmatically put subviews in it. It's ok, but how can I lay automatically the subviews next to each other?
Thanks in advance!
You can't. The view hierarchy in UIKit--like the view hierarchy in most UI frameworks--uses explicit layout.
Your comment asks about HTML-like floating; the box model stuff that HTML/CSS uses was designed to serve a very different goal (flowing document layout) than what UIKit is for, and so there's no real analogy in the framework.
UIViews do support automatic re-layout on resize/frame change of the parent view (you can say whether a subview should resize, how, and where it should be "pinned" to), through the autoresizing mask property, but I don't think that's what you're asking for.
You could, if you were inclined, build a set of methods, perhaps as a category on UIView, that let you add subviews that had their frame origins adjusted automatically based on existing subviews.
The position of the subviews is dictated by their frame property. So you need to set their frames such that they line up next to each other.
If they are all the same size you can do with some simple math and CGRectMake(). If they will have different sizes, you can use CGRectDivide() to break a large rect into smaller rects. CGRectInset() is also useful, in case you want some padding between them.
I'm trying to show the "selection" of a certain sub-string in a
gtk.TextView by drawing a border around the word. The only way to mark
text in a TextView that I've found so far is by placing TextTags with
modified properties. This does not seem to offer a way to draw a border,
though, DOES GTK SUPPORT THIS OR IS THIS A PROBLEM WITH ONLT PYGTK
I figured out how to draw on a text view !!!
To begin with lets assume the reference to your gtk.TextView is in a variable called viewer, Inside one of ur classes
Also the draw function has to be called with an event called expose-event else the drawings will be refreshed and will not stay on the screen
The next part is the gtk.TextView consists of 7 types of gtk.gdk.windows on which u can draw
gtk.TEXT_WINDOW_WIDGET
gtk.TEXT_WINDOW_TEXT
gtk.TEXT_WINDOW_LEFT - not displayed by default
gtk.TEXT_WINDOW_RIGHT - not displayed by default
gtk.TEXT_WINDOW_TOP - not displayed by default
gtk.TEXT_WINDOW_BOTTOM
gtk.TEXT_WINDOW_PRIVATE
For the drawing to appear on gtk.TextView We have to draw on gtk.TEXT_WINDOW_TEXT
An Example Code is as shown Below
if(viewer!=None):
viewer.connect("expose-event", expose_view)
self.drawable=viewer.get_window(gtk.TEXT_WINDOW_TEXT)
def expose_view(self,window,event):
if(self.drawable!=None):
self.drawable.draw_line(self.drawable.new_gc(),1,1,30,30)
# (1,1) and (30,30) are the coordinates and u can give the values accordingly
In a gtk.TextBuffer tags are used to set one or more pre-defined text attributes. Without subclassing, this is limited to the properties of a gtk.TextTag, and doesn't include anything akin to a border or outline property. There is no difference between PyGTK and plain GTK+ in this regard.
While somewhat hacky, the easiest way to do what you want to do is to connect to the expose-event of your gtk.TextView, get the coordinates of your string and draw on event.window, which is the gdk.Window of the event provided in the expose callback.
(Note that you don't have to get and store the gtk.TEXT_WINDOW_TEXT window, you just need to check what window the expose event is for in the callback, probably ignoring the expose if it's not for the text window.)
Instead, you could presumably subclass one or more of TextBuffer/TextView/TextTag to add a border tag, but whether it's reasonable to do so is another question.