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https://github.com/igorski/bitmappery

Browser based non-destructive photo editor with layering, masking, customizable brushes and cloud storage integration for all your web based working.
https://github.com/igorski/bitmappery

browser image-editor image-processing photo-editor photos photoshop pwa pwa-apps typescript vue vuejs wasm webassembly

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Browser based non-destructive photo editor with layering, masking, customizable brushes and cloud storage integration for all your web based working.

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README 

        
# BitMappery



## So you are rebuilding Photoshop in the browser ?



No, I'm building a tool that does the bare minimum what I require and what I don't

find in other open source tools. That doesn't mean of course that contributions

related to Photoshop-esque features aren't welcomed.



### All hand-written ?



Yep, though it helps having worked in the photo software industry for five years, having

tackled the problems before. Also, BitMappery is reusing [zCanvas](https://github.com/igorski/zCanvas)

under the hood for rendering and bitmap blitting. BitMappery is written on top of [Vue](https://github.com/vuejs/vue) using [Vuex](https://github.com/vuejs/vuex) and [VueI18n](https://github.com/kazupon/vue-i18n).



## The [Issue Tracker](https://github.com/igorski/bitmappery/issues) is your point of contact



Bug reports, feature requests, questions and discussions are welcome on the GitHub Issue Tracker, please do not send e-mails through the development website. However, please search before posting to avoid duplicates, and limit to one issue per post.



Please vote on feature requests by using the Thumbs Up/Down reaction on the first post.



## Model



BitMappery works with entities known as _Documents_. A Document contains several _Layers_, each of

which define their content, transformation, _Effects_, etc. Each of the nested entity properties

has its own factory (see _/src/factories/_). The Document is managed by the Vuex _document-module.js_.



The types for each of these are defined in `/src/definitions/document.ts`.



## Document rendering and interactions



The Document is rendered one layer at a time onto a Canvas element, using [zCanvas](https://github.com/igorski/zCanvas). Both the rendering and interaction handling is performed by dedicated "Sprite" classes.



All layer rendering and layer interactions are handled by _/src/rendering/canvas-elements/layer_sprite.js_.

Note that the purpose of the renderer is solely to delegate interactions events to the Layer entity. The

renderer should represent the properties of the Layer, the Layer should never reverse-engineer from the onscreen

content (especially as different window size and scaling factor will greatly complicate these matters when

performed two-way).



All interactions that work across layers (viewport panning, layer selection by clicking on non-transparent

pixels and drawing of selections) is handled by a single top level sprite that covers the entire zCanvas area.

This sprite is _/src/rendering/canvas-elements/interaction-pane.js_.



Interactions that start/end from _outside the canvas_ (for instance the opening/closing of a selection or the

drawing of a brush stroke outside of the canvas area) are handled by _document-canvas.vue_ where the global DOM coordinates are translated to coordinates relative to the canvas document before being forwarded to the zCanvas

event handler. See "Rendering concepts" below for more details on screen-to-document coordinates.



Rendering of transformations, text and effects is an asynchronous operation handled by _/src/services/render-service.js_. The purpose of this service is to perform and cache repeated operations and eventually maintain

the source bitmap represented by the LayerSprite. The LayerSprite invokes the rendering service whenever

Layer content changes and manages its own cache.



All types related to the editor are either defined in `src/definitions/editor.ts` or the more specifically

named files.



### Rendering concepts



BitMappery follows the concepts of the display list as listed in the zCanvas wiki, where BitMappery's

document layers are visualized as separate Sprites which can be manipulated as separate interactive on-screen

elements. BitMappery additionally adds additional logic related to the viewing of large scale content in smaller fragments.



The zCanvas' DOM element (an _HTMLCanvasElement_ instance) is basically as large as the available area inside the

DOM window allows. The BitMappery document displayed inside may however be larger or smaller than the canvas itself

(depending on the _zoom level_ which is - not yet - standardized in the zCanvas package and custom written for BitMappery using the `ZoomableCanvas` and `ZoomableSprite` classes).



What determines the visible area of the zoomed document is the _viewport_. As such, interactions with the zCanvas

element must be _translated_ from global DOM coordinates to a point relative to the BitMappery document, taking

into account the current scaling factor and viewport offset. This is handled automatically by all event handlers

delegated through zCanvas and the sprites, but needs care when performing rendering operations (such as drawing)

and translating these to (non-zoomed and non-panned) source bitmaps.



## State history



Mutations can be registered in state history (Vuex _history-module.js_) in order to provide undo and redo

of operations. In order to prevent storing a lot of changes of the same property (for instance when dragging a slider), the storage of a new state is deferred through a queue. This is why history states are enqueued by _propertyName_:



When enqueuing a new state while there is an existing one enqueued for the same property name, the first state is updated so its redo will match that of the newest state, the undo remaining unchanged. The second state will not

be added to the queue.



It is good to understand that the undo/redo for an action should be considered separate

from the Vue component that is triggering the transaction, the reason being that the component can be

unmounted at the moment the history state is changed (and the component is no longer active).



That's why undo/redo handlers should either work on variables in a local scope, or on the Vuex store

when mutating store properties. When relying on store state and getters, be sure to cache their

values in the local scope to avoid conflicts (for instance in below example we cache _activeLayerIndex_

as it is used by the undo/redo methods to update a specific Layer. _activeLayerIndex_ can change during

the application lifetime before the undo/redo handler fires which would otherwise lead to the _wrong Layer_

being updated.



```typescript

update( propertyName: string, newValue: any ): void {

    // cache the existing values of the property value we are about to mutate...

    const existingValue = this.getterForExistingValue;

    // ...and the layer index that is used to identify the layer containing the property

    const index = this.activeLayerIndex;

    const store: Store = this.$store;

    // define the method that will mutate the existing value to given newValue

    const commit = (): void => store.commit( "updateLayer", { index, opts: { newValue } });

    // and perform the mutation directly

    commit();

    // now define and enqueue undo/redo handlers to reverse and redo the commit mutation

    enqueueState( propertyName, {

        undo(): void {

            store.commit( "updateLayerEffects", { index, opts: { existingValue } });

        },

        redo(): void {

            commit();

        },

    });

}

```



Whenever an action (that requires an undo state) can be triggered in multiple locations (for instance

inside a component and as a keyboard shortcut in `@/src/services/keyboard-service`), you can

create a custom handler inside `@/src/factories/action-factory` to avoid code duplication.



## Third party storage integration



Requires you to register a client id or access token in the developer portal of the third party

storage provider. Currently, there is support for [Dropbox](https://www.dropbox.com/developers/apps), [Google Drive](https://console.cloud.google.com/) and S3 storage.



You can enable each of these integrations by providing the required key values for your configuration

by creating a local `.env.local`-file which will contain your custom configuration. You can create this

file by duplicating the contents of the `.env`-file provided in the repository.



## Project setup



The project setup is two-fold. You can get all the dependencies through NPM as usual:



```

npm install

```



after which you can run:



* ```npm run dev``` to start a local development server with hot module reload

* ```npm run build``` to compile a production package

* ```npm run test```  to run the unit tests

* ```npm run lint``` to run the linter on the source files



The above will suffice when working solely on the JavaScript side of things.



## Docker based self hosted version



#### Step 1 : Clone the BitMappery project into a local folder :



```bash

git clone https://github.com/igorski/bitmappery.git

```



#### Step 2 : Build the image using the provided Dockerfile :



```bash

docker build -t bitmappery .

```



#### Step 3 : Once the image is built, run the container and bind the ports :



```bash

docker run -d -p 5173:5173 --name bitmappery-container bitmappery

```



Once the container is started, you can access BitMappery at `http://localhost:5173`



## WebAssembly



BitMappery can also use WebAssembly to _potentially_ increase performance of image manipulation.

WebAssembly filtering is a user controllable feature in the preferences pane, as long as the `.env` file has set

support for `VITE_ENABLE_WASM_FILTERS` to true.



The source code is C based and compiled to WASM using [Emscripten](https://github.com/emscripten-core/emscripten). Because this setup is a little more cumbersome, the repository contains precompiled binaries in the _./src/wasm/bin/_-folder meaning you can

omit this setup if you don't intend to make changes to these sources.



If you do wish to make contributions on this end, to compile the source (_/src/wasm/_) C-code to WASM, you

will first need to prepare your environment (note the last _source_ call does not permanently update your paths):



```bash

git clone https://github.com/emscripten-core/emsdk.git

cd emsdk

./emsdk install latest

./emsdk activate latest

source ./emsdk_env.sh

```



now you can compile all source files to WASM using:



```

npm run wasm

```



### Benchmarks



On a particular (deliberately low powered) configuration, running all filters at their heaviest setting on a particular source takes:



* 7000+ ms in JavaScript

* 558 ms in WebAssembly

* 484 ms in JavaScript inside a Web Worker

* 603 ms in WebAssembly inside a Web Worker



Note that the WebAssembly Web Worker takes a performance hit from converting the ImageData buffer

to float32 prior to allocating the buffer in the WASM instance's memory. This could benefit from

further tweaking to see if it gets closer to the JavaScript Web Worker performance.



However, as in the current setup the JS solution alone is performant enough _and you would need to write the

filter code twice_, the default for WASM is disabled.