- #Letterspace android how to#
- #Letterspace android android#
- #Letterspace android software#
- #Letterspace android code#
The fourth parameter is the paint object, we will cover the purpose of this parameter soon. You need to ensure the rect that is passed in is properly scaled. You need to be careful with this, since it can quite easily stretch the bitmap, as the Canvas calls don’t take into account the aspect ratio of the provided image. Tip: Make sure your RectF object that you pass into the drawBitmap function is scaled with the correct aspect ratio otherwise your output may be stretched The third parameter is a RectF object which represents the scale and translation of the bitmap that you want to draw on screen. The second parameter here allows us to pass in the portion of the bitmap that you want to render, when passing in null the whole bitmap will be rendered. canvas.drawBitmap(bitmap, null, rect, paint) The method for doing this is just called drawBitmap and it takes in the bitmap object that is loaded up either with Android’s built-in mechanisms, or with Glide. One of the most common drawing operations is to draw a bitmap (image) onto the canvas. There are many different things you can draw onto a Canvas.
#Letterspace android software#
For more information about the differences between hardware rendering and software rendering, read this post. For instance, some commands are just not supported with hardware rendering, or only supported from a certain API level. This can affect the appearance of some of the drawing commands.
It’s worth noting at this point that any Canvas created programmatically without using a View, will be software rendered and not hardware rendered. You can also get access to a Canvas object by programatically creating one in code, like this: val bitmap = Bitmap.createBitmap(width, height, _8888) You can then include this view inside your layout XML and this will then automatically invoke the onDraw method of the Custom View. Called when the view should render its content. class CustomView constructor(context: Context,Īttrs: AttributeSet? = null, defStyleAttr: Int = 0) This will then allow you to override the onDraw method, which has a Canvas as a parameter. In order to get access to a Canvas instance, you will need to create a class that extends from View.
#Letterspace android how to#
Paint - to describe how to draw the commands.Drawing commands - to indicate to the canvas what to draw.Canvas - to run the drawing commands on.A bitmap or a view - to hold the pixels where the canvas will be drawn.To draw onto a canvas in Android, you will need four things: It is up to you to ensure that your items are laid out correctly (Alternatively, you might want to use some of the built-in layout mechanisms for this - such as LinearLayout). The last draw command will be the topmost item drawn onto your canvas. This will ensure that your drawing looks consistent across devices with different pixel densities.Ĭanvas draw commands will draw over previously drawn items. This means you need to translate any dp values into px before calling any canvas operations. When working with the Canvas, you are working with px and not dp, so any methods such as translating, or resizing will be done in pixel sizes.
The y axis is positive downwards, and x axis positive towards the right.Īll elements drawn on a canvas are placed relative to the point.
#Letterspace android android#
The coordinate system of the Android canvas starts in the top left corner, where represents that point. Canvas Coordinate System The Android Canvas Coordinate System
#Letterspace android code#
It is useful to know that SKIA is used in the underlying code for Android, so when you get stuck trying to understand how a certain API works, you can look at the source for SKIA to gain a deeper understanding. Tip: Check out the SKIA source code for a deeper understanding of the Canvas implementation. Once you understand how the Canvas works on Android, the same drawing concepts apply to many other different platforms. SKIA is used on platforms such as Google Chrome, Firefox OS, Flutter, Fuschia etc. The SKCanvas comes from SKIA, which is a 2D Graphics Library that is used on many different platforms. The Canvas class is not a new concept, this class is actually wrapping a SKCanvas under the hood. It is basically, an empty space to draw onto. The saying “a blank canvas” is very similar to what a Canvas object is on Android. What is a Canvas?Ĭanvas is a class in Android that performs 2D drawing of different objects onto the screen. Imagine being able to draw anything* your heart desires just with some basic shapes, paths and bitmaps? Well, the Android Canvas gives you just that ability. Diving into using the Android Canvas class can unlock magical super powers you never knew you had 🤯.
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