SUSI is an artificial intelligence for interactive chat bots. For making it more user friendly and interactive we add a lot of images in the form of drawable resources in the SUSI Android App (https://github.com/fossasia/susi_android). Most of these drawables are in the form of PNGs. There are certain problems associated with the use of PNG images.

1. PNGs cannot be scaled without losing quality. Due to which for the same PNG image we have to include separate images of varied quality. Otherwise the image will become blur.
2. PNGs tends to take large disk space which can be easily reduced with the use of vector images.
3. PNGs have fixed color and dimensions which cannot be changed.

Due to the above shortcomings of PNG images we decided to use vector drawable images instead of them.

Advantages associated with Vector images

1. They can be scaled to any size without the loss in quality. Thus we need to include only a single image in the app and not of varied qualities.
2. They are very small in size as compared to PNGs.
3. They can be easily modified programmatically in XML file unlike PNGs.

Using Vector Images in Android Studio

Android Studio provide tools by which we can directly import vector drawables in the project. To import Vector images go to File>New>Vector Assets in studio.

From here we can choose the icon we want to include in our project and click OK. The icon will appear in the drawables directory and can be used anywhere in the projects.

Implementation in SUSI Android

In Susi Android we have used various vector images such as arrows, pointer and even the logo of the app. Here below is the logo of SUSI.

This is actually a vector image below we will see the code required to get this logo as the output.

<vector android:height="50dp" android:viewportHeight="279.37604"

  android:viewportWidth="1365.2" android:width="220dp" xmlns:android="http://schemas.android.com/apk/res/android">

<path android:fillColor="#ffffff"

      android:pathData="M127.5,7.7c-26.8,3.3 -54.2,16.8 -75.9,37.4 -11.8,11.1 -20.4,22.9 -28.1,38.4 -8.9,17.8 -12.8,32.1 -13.7,51l-0.3,6 39,0 39,0 0.3,-4c0.7,-12.1 6.8,-24.1 17.2,-34.5 8.5,-8.4 16.2,-13.4 25.9,-16.7l6.6,-2.2 81.3,-0.1 81.2,0 0,-38 0,-38 -84.7,0.1c-46.7,0.1 -86.1,0.4 -87.8,0.6z" android:strokeColor="#00000000"/>

  <path android:fillColor="#ffffff"

      android:pathData="M319.2,11.3l-4.3,4.3 0.3,103c0.4,113.2 0,105.9 6.4,118.6 10.8,21.3 35.1,41.9 56.2,47.3 8.5,2.3 99.1,2.2 107.7,0 18.7,-4.9 39.2,-20.7 51.5,-39.7 3.4,-5.1 7.1,-12.2 8.3,-15.8l2.2,-6.5 0.5,-103.3 0.5,-103.3 -4.5,-4.4 -4.6,-4.5 -31.5,0 -31.5,0 -4.7,4.8 -4.7,4.8 0,93 0,93 -3.3,3.2 -3.3,3.2 -29,0 -29,0 -2.6,-2.7 -2.7,-2.8 -0.7,-94.2 -0.7,-94.2 -4.3,-4 -4.2,-4.1 -31.9,0 -31.9,0 -4.2,4.3z" android:strokeColor="#00000000"/>

  <path android:fillColor="#ffffff"

      android:pathData="M680,7.6c-31.6,4.8 -56.1,17.3 -79,40.3 -23.2,23.3 -36.3,50.5 -38.9,80.9 -0.5,5.9 -0.7,11 -0.4,11.4 0.2,0.5 17.7,0.8 38.8,0.8l38.4,0 0.6,-4.8c3.2,-23.2 21.3,-44.1 44.7,-51.3 5.6,-1.8 10.6,-1.9 86.6,-1.9l80.7,0 -0.3,-38 -0.2,-38 -84.3,0.1c-46.3,0.1 -85.3,0.3 -86.7,0.5z" android:strokeColor="#00000000"/>

  <path android:fillColor="#ffffff"

      android:pathData="M869.1,13.4l-4.1,6.4 0,126.4 0,126.3 4.8,6.7 4.7,6.8 31.6,0 31.6,0 4.7,-7 4.6,-7 0,-125.7 0,-125.8 -4.7,-6.7 -4.8,-6.8 -32.1,0 -32.1,0 -4.2,6.4z" android:strokeColor="#00000000"/>

  <path android:fillColor="#ffffff"

      android:pathData="M222.5,152.2c-0.2,0.7 -0.9,4.2 -1.5,7.7 -3.4,19.5 -19.4,38 -40,46.4l-5.5,2.2 -83,0.5 -83,0.5 -0.3,37.8 -0.2,37.8 89.2,-0.3 89.3,-0.3 9.6,-2.7c57.7,-16.3 100.1,-67.4 102.1,-123.3l0.3,-7 -38.3,-0.3c-30.1,-0.2 -38.3,0 -38.7,1z" android:strokeColor="#00000000"/>

  <path android:fillColor="#ffffff"

      android:pathData="M774.5,152.2c-0.2,0.7 -0.9,4.1 -1.5,7.5 -3.3,19.2 -18.8,37.3 -39.4,46.2l-6.1,2.6 -83,0.5 -83,0.5 -0.3,37.7 -0.2,37.8 85.9,0c93.7,0 91.4,0.1 110.1,-5.9 26.4,-8.5 53.3,-28.4 69.8,-51.7 15.2,-21.3 25.1,-50.1 24,-69.9l-0.3,-6 -37.8,-0.3c-29.7,-0.2 -37.8,0 -38.2,1z" android:strokeColor="#00000000"/>

  <path android:fillColor="#ffffff" android:pathData="m1146.99,0 l-1.38,1.19c-0.76,0.66 -1.85,1.61 -2.43,2.13 -0.58,0.51 -1.75,1.54 -2.61,2.28 -1.52,1.31 -1.58,1.41 -2.4,3.53 -0.46,1.2 -0.92,2.37 -1.01,2.59 -30.55,82.93 -61.62,165.72 -96.03,259.63 0,0.08 1.61,1.88 3.57,3.98l3.57,3.84 33.47,-0.04 33.47,-0.04c12.28,-35.6 25.13,-72.47 37.4,-107.27 0.06,-0.25 0.28,-0.64 0.5,-0.88 0.37,-0.41 0.61,-0.43 4.2,-0.43 3.63,0 3.83,0.02"/>

  <path android:fillColor="#ffffff" android:pathData="m967.09,279.18c-2.48,-3.74 -4.97,-7.04 -8.09,-11.76l0.09,-43.92c3.34,-5.26 5.31,-6.73 8.42,-11.51 17.91,0.02 34.3,0.26 50.88,0.26 3.21,4.88 4.09,6.72 7.81,12.66 -0.05,13.98 0.1,27.96 -0.12,41.94 -2.9,4.2 -4.27,7.42 -7.78,12.18 -18.81,-0.04 -35.43,0.2 -51.21,0.15z"/>

  <path android:fillColor="#ffffff"

      android:pathData="m1287.3,6.59 l-4.1,6.4 0,126.4 0,126.3 4.8,6.7 4.7,6.8 31.6,0 31.6,0 4.7,-7 4.6,-7 0,-125.7 0,-125.8 -4.7,-6.7 -4.8,-6.8 -32.1,0 -32.1,0 -4.2,6.4z" android:strokeColor="#00000000"/>


</vector>

In this code we can easily change the color and minor details for the logo which could have been not possible if the logo was in PNG format. Also we don’t need multiple logo images of varied qualities as it can be scaled without decreasing quality.

Resources

• How to use vector icons in your apps. https://medium.com/@webalys/die-png-die-how-to-use-vector-icons-in-your-apps-d884c9c63e93
• Introduction to Vector images in Android: ttps://thenewstack.io/vector-images-come-android-devs-need-know/