Svetlozar Kostadinov

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Software Developer

Android developer

Endava

Architecture and development of a native Android payment SDK for a large European payment service provider. Responsible for creating a pluggable framework, API design and extensible UI components for handling various payment methods (incl. credit cards + 3DS, SEPA, PayPal, etc.). I worked over card scanning feature using camera and OCR. I participated in the design of the security scheme appropriate for mobile SDK authentication.

Tools: Kotlin, Coroutines, OkHttp, Retrofit, Moshi, REST, JSON, Material Components, ViewModel, LiveData, Chrome Custom Tabs, JUnit, Mockito, Robolectric.

Android & Python developer

Endava

The customer was in the wrist watch industry. The project had Android and iOS applications and complex image recognition backend logic. The client is a worldwide electronics company, primary known for its watches; it is also the core company is a Japanese global corporate group based in Tokyo.

I had 2 distinct roles in the project:

1. Python backend developer May 2018 – June 2018

Implemented a small image recognizer backend with Python and Google Cloud Vision API. Image pre-processing, calibration and analysis with OpenCV. Post-processing with various Machine Learning techniques for optimizing the recognition rate. The recognizer was written as a standalone Python command line tool which then was wrapped into a Java Spring REST service. The system was able to recognize a concrete watch model from a photo within >90% probability.

Technical skills and tools: Python, Google Cloud Vision API, OpenCV, image processing.

1. Android developer July 2018 – Sep 2018

I was responsible for developing the Android client. It was a non-Material style app with about 16 screens and relatively complex navigation flows. The app included camera, files downloader, authentication with Facebook and Google accounts, notifications, synchronization with the REST backend. I have combined successfully some latest technologies and advancements in the Android industry: 100% Kotlin, MVI fully reactive unidirectional flow, immutable models. The result was a stable app with a small, easily testable and clean codebase.

Technical skills and tools: Android: Kotlin, KotlinX, Dagger-Android, OkHttp3, Retrofit2, RxJava2, Moshi, Mosby-MVI, Fotoapparat, ThreeTenABP, Glide, Timber, LeakCanary, Junit, Espresso, Mockito.

Android Developer

Indie

End-to-end developer and designer of MovieLovers - an Android app for cinema and TV fans. Provides a comprehensive information about movies, shows and celebrities. The accent of the app is Material Design with a lot of attention to detail.

• Unidirectional reactive architecture based on Mosby-MVI.
• Separated Data/Domain/Presentation layers and fully immutable models.
• Consuming RESTful web services, pagination, disk and memory caching, full state restoration.
• Can operate fully offline with connectivity alerts.
• Using nested RecyclerViews with layout performance optimizations via shared RecyclerView pools, image preloading and more.
• Heavy use of imagery, custom-crafted animations, transitions and other visual effects.
• Gesture navigation.

App is available for free at:

• Play Store
  
• Amazon

Environment: Kotlin, RxJava2, Dagger2, Retrofit2, TMDB, GSON, Glide, Mosby-MVI, Conductor, PaperParcel.

More details and screenshots: Portfolio.

Android Developer

Hi-Tech Research & Consulting, Varna

End-to-end developer of GeoWorld app - advanced Android geocoordinate converter for geodesists and field surveyors. Offers unique features on the market. Role highlights:

• Solo developer responsible for all stages of the development lifecycle - from idea to maintenance, including deployment, localization, end-user documentation, analytics, customer tech support.
• Designed and implemented responsive UI/UX in portrait and landscape for phones and tablets following Material Design guidelines with usage of simple animations. Early adopted the new Material appearance.
• Very good understanding of the Java OOP design patterns and paradigms like Clean Architecture, MVC, MVP and MVVM.
• Gained in-depth knowledge of the Android platform, tooling and the Support libraries.
• Proficient in subjects like: Dependency Injection, Data Binding, SQLite for offline database storage, Accounts and sync.
• Fluent in multi-threading with Thread, Handler, AsyncTask, Service, IntentService, Loader, RxJava.
• Extensively worked with the most used widgets like RecyclerView, DrawerLayout, CoordinatorLayout, ActionBar, ViewPager, CardView, ProgressBar, fragments, layouts, dialogs, toasts, implemented custom widgets with canvas drawing, full-screen activities.
• Crafted XML layouts with precise measurements complying the Material Design spec.
• Experience with Android API’s like Intents, Runtime Permissions, Notifications, ContentProvider, AccountManager, Camera, Sensors, GPS, Location Service, Files API, Internal/External Storage, File and Document Providers, MediaStore, MediaPlayer API.
• Experience with Google Maps API and Google Places API.
• Implemented an in-app store for monetization based on unlockable app features and content using the In-App Billing library.
• Implemented banner and interstitial Ads with AdMob and Ogury.co.
• Awareness of the common pitfalls and quirks associated with Android development.
• Extensively used libraries like RxJava, Dagger2, GreenDAO, Picasso, Retrofit, GSON, OkHttp, Jsoup, JodaTime, ButterKnife, Parceler, PaperParcel, EventBus, Binding-collection-adapters, KotlinX, Timber, Stetho, DexCount.
• Experience with RESTful web services, HTTP authentication, OAuth2, XML, JSON.
• Experience with scraping HTML web sites and using them as emulation of REST API with the help of Retrofit and Jsoup.
• Experience in database design using SQLite and Spatialite.
• Refactored a large fragment-based codebase into clean Reactive MVVM + Data Binding architecture.
• Experience in unit testing and integration testing on device and emulator using JUnit, Mockito, Espresso & UIAutomator.
• Implemented continuous integration using CircleCI for the project’s Git repository in BitBucket.
• Successfully set up ACRA bug reporting backend and Google Analytics and used it to collect anonymous data about runtime problems to keep the users from experiencing fatal crashes.
• Implemented a one-click APK publishing process for all app flavors and CPU architectures.
• Knowledge of integration, building and debugging of multi-architecture C/C++/JNI projects using Android NDK.
• Used Git and Mercurial as version control system (VCS).
• Refactored into Kotlin to improve code clarity and simplicity of core classes.
• Ported Spatialite database for use in Android as a geospatial engine: android-spatialite.
• Hands-on experience with hybrid apps using Cordova/PhoneGap.
• Hands-on experience with geospatial and map technologies like Spatialite, GeoNode, OsmDroid, OpenLayers, Leaflet, MapBox, MBTiles, GeoDjango, GeoServer, WMS, WFS.
• Studied the principles, standards, methods, categories of geospatial map projections and coordinate transformations, geodetic datums and successfully applied the knowledge into a complete product.
• Written a detailed 70 page end-user manual in Google Docs with screenshots, diagrams, tables and styles.
• Designed a vector logo and multiple icons in InkScape.

More details and screenshots: Portfolio.

Java SE Developer

Hi-Tech Research & Consulting, Varna

PanelHome3D is an innovative Java desktop CAD software developed for companies, producers of polystyrene panels for building construction. Heavily customized fork of the popular open-source project SweetHome 3D. Sketching of simple construction plans of buildings. Analyzes the entire building geometry (walls, floor, ceiling, roof) and automatically generates a list of precise geometry shapes of the sliced panel pieces. The output geometry data is collected and formatted into a book of printable sheets. This book is a plan for the construction workers to assemble to panel pieces into complete buildings.

Environment: Eclipse, Java SE 6, MVC, XML, Swing, AWT, Canvas, JIDE UI toolkit, Substance, Flamingo, JavaGeom, jMonkeyEngine, JNLP, Applet.

• Solo developer of the project (the fork);
• Implemented custom Swing MVC components;
• Heavy use of AWT Canvas and 2D graphics;
• Implemented Print Preview zoomable page layout;
• Developed a Roof editor (3rd party algorithm);
• Developed a Wall editor;
• Developed a 2D polyline sketcher with advanced snapping;
• Implemented dynamic 3D scene view with jMonkeyEngine.

More details and screenshots: Portfolio.

C++ Developer

Hi-Tech Research & Consulting, Varna

Buildware 3D is a Windows CAD modeler software from the early 2000s written in C++ and based on the OpenCASCADE engine and OpenGL. Has 2D/3D modelling environment for interactive construction of geometry primitives, coordinate systems, layers, snapping, print layouts, property list UI. Heavy use of COM (the predecessor of .NET). Has a small core and modular design for high flexibility and extensibility through a custom plug-in framework based on COM interfaces. I was a member of the team of 3-5 developers.

Environment: Visual C++, MFC, COM, ATL, IDL, WinAPI, GDI, OpenGL, OpenCASCADE, Prof-UIS.

Highlights of my participation in the project:

• Working with very large codebase;
• Extending the existing codebase with additional features, improving legacy code, bug fixing;
• Responsible for the GUI and the plug-in subsystems;
• Implementing COM plugins which provide interactive operations over visual geometry objects like polylines, splines, boxes, prisms and more.
  • Boolean operations (Cut, Union, Intersection);
  • 2D operations (Move, Rotate, Mirror, Scale);
  • 3D operations (Fillet, Chamfer, Extrude);
• Integration of the Prof-UIS MFC GUI library: implementing multi-pane layout, tree-view, toolbars, menus and a multi-selection PropertyGrid with binding to COM objects;
• Participated in an effort to integrate a parametric CAD modelling core provided by OpenCASCADE.

More details and screenshots: Portfolio.

BSc in Computer Systems and Technologies

Graduated from Technical University of Varna.

Secondary education

Gymnasium of Finances and Economics - Dobrich.

First PC

Started learning computers and programming on my first PC: 386DX 40 MHz. My first programs were Turtle graphics in Basic and Pascal.

Hello World!

Born in Dobrich, Bulgaria.