NativeScript Bitmap Factory

A NativeScript module for creating and manipulating bitmap images.

NativeScript Toolbox

This module is part of nativescript-toolbox.

License

MIT license

Platforms

• Android
• iOS

Installation

Run

tns plugin add nativescript-bitmap-factory

inside your app project to install the module.

Usage

import BitmapFactory = require("nativescript-bitmap-factory");
import KnownColors = require("color/known-colors");

// create a bitmap with 640x480
var bmp = BitmapFactory.create(640, 480);

// work with bitmap and
// keep sure to free memory
// after we do not need it anymore
bmp.dispose(() => {
    // draw an oval with a size of 300x150
    // and start at position x=0, y=75
    // and use
    // "red" as border color and "black" as background color.
    bmp.drawOval("300x150", "0,75",
                 KnownColors.Red, KnownColors.Black);
      
    // draw a circle with a radius of 80
    // at the center of the bitmap (null => default)
    // and use
    // "dark green" as border color           
    bmp.drawCircle(80, null,
                   KnownColors.DarkGreen);
                
    // draws an arc with a size of 100x200
    // at x=10 and y=20
    // beginning at angle 0 with a sweep angle of 90 degrees
    // and a black border and a yellow fill color    
    bmp.drawArc("100x200", "10,20",
                0, 90,
                KnownColors.Black, KnownColors.Yellow);
                   
    // set a yellow point at x=160, y=150
    bmp.setPoint("160,150", "ff0");
    
    // draws a line from (0|150) to (300|75)
    // with blue color
    bmp.drawLine("0,150", "300,75", '#0000ff');
    
    // writes a text in yellow color
    // at x=100, y=100
    // by using "Roboto" as font
    // with a size of 10
    bmp.writeText("This is a test!", "100,100", {
        color: KnownColors.Yellow,
        size: 10,
        name: "Roboto"
    });
    
    // returns the current bitmap as data URL
    // which can be used as ImageSource
    // in JPEG format with a quality of 75%
    var data = bmp.toDataUrl(BitmapFactory.OutputFormat.JPEG, 75);
    
    // ... and in Base64 format
    var base64JPEG = bmp.toBase64(BitmapFactory.OutputFormat.JPEG, 75);
    
    // ... and as ImageSource
    var imgSrc = bmp.toImageSource();
});

Functions

Platform specific stuff

You can access the nativeObject property to access the platform specific object.

For Android this is a Bitmap object and for iOS this is an UIImage object.

To check the platform you can use the android and ios properties which have the same values as the corresponding properties from application core module.

Android

You also can access the underlying Canvas object by __canvas property.

iOS

You also can access the underlying CGImage object by__CGImage property.

Data types

IArgb

Stores data of an RGB value with alpha value.

These values can also be submitted as strings (like #ff0 or ffffff) or numbers.

interface IArgb {
    /**
     * Gets the alpha value.
     */
    a: number;

    /**
     * Gets the red value.
     */
    r: number;

    /**
     * Gets the green value.
     */
    g: number;

    /**
     * Gets the blue value.
     */
    b: number;
}

IBitmapData

Used by toObject() method.

interface IBitmapData {
    /**
     * Gets the data as Base64 string.
     */
    base64: string;

    /**
     * Gets the mime type.
     */
    mime: string;
}

IFont

Font settings.

interface IFont {
    /**
     * Anti alias or not.
     */
    antiAlias?: boolean;

    /**
     * Gets the custom forground color.
     */
    color?: string | number | IArgb;
    
    /**
     * Gets the name.
     */
    name?: string;

    /**
     * Gets the size.
     */
    size?: number;
}

IPoint2D

Coordinates, can also be a string like 0,0 or 150|300.

interface IPoint2D {
    /**
     * Gets the X coordinate.
     */
    x: number;
    
    /**
     * Gets the Y coordinate.
     */
    y: number;
}

IPoint2D

Size, can also be a string like 0,0 or 150x300.

interface ISize {
    /**
     * Gets the height.
     */
    height: number;
    
    /**
     * Gets the width.
     */
    width: number;
}

OutputFormat

Supported output formats.

enum OutputFormat {
    /**
     * PNG
     */
    PNG = 1,

    /**
     * JPEG
     */
    JPEG = 2,
}

Bitmap

interface IBitmap {
    /**
     * Get the android specific object provided by 'application' module.
     */
    android: AndroidApplication;

    /**
     * Clones that bitmap.
     */
    clone(): IBitmap;

    /**
     * Crops that bitmap and returns its copy.
     */
    crop(leftTop?: IPoint2D | string,
         size?: ISize | string): IBitmap;

    /**
     * Gets or sets the default color.
     */
    defaultColor: IPoint2D | string | number;

    /**
     * Disposes the bitmap. Similar to the IDisposable pattern of .NET Framework.
     */
    dispose<T, TResult>(action?: (bmp: IBitmap, tag?: T) => TResult,
                        tag?: T): TResult;

    /**
     * Draws a circle.
     */
    drawCircle(radius?: number,
               center?: IPoint2D | string,
               color?: string | number | IArgb, fillColor?: string | number | IArgb): IBitmap;

    /**
     * Draws an arc.
     */
    drawArc(size?: ISize | string,
            leftTop?: IPoint2D | string,
            startAngle?: number,
            sweepAngle?: number,
            color?: string | number | IArgb, fillColor?: string | number | IArgb): IBitmap;

    /**
     * Draws a line.
     */
    drawLine(start: IPoint2D | string, end: IPoint2D | string,
             color?: string | number | IArgb): IBitmap;

    /**
     * Draws an oval circle.
     */
    drawOval(size?: ISize | string,
             leftTop?: IPoint2D | string,
             color?: string | number | IArgb, fillColor?: string | number | IArgb): IBitmap;

    /**
     * Draws a rectangle.
     */
    drawRect(size?: ISize | string,
             leftTop?: IPoint2D | string,
             color?: string | number | IArgb, fillColor?: string | number | IArgb): IBitmap;

    /**
     * Gets the color of a point.
     */
    getPoint(coordinates?: IPoint2D | string): IArgb;

    /**
     * Gets the height of the bitmap.
     */
    height: number;

    /**
     * Get the iOS specific object provided by 'application' module.
     */
    ios: iOSApplication;

    /**
     * Inserts another image into that bitmap.
     */
    insert(other: any,
           leftTop?: IPoint2D | string): IBitmap;
    
    /**
     * Gets if the object has been disposed or not.
     */
    isDisposed: boolean;

    /**
     * Gets the native platform specific object that represents that bitmap.
     */
    nativeObject: any;

    /**
     * Normalizes a color value.
     */
    normalizeColor(value: string | number | IArgb): IArgb;

    /**
     * Creates a copy of that bitmap with a new size.
     */
    resize(newSize: ISize | string): IBitmap;

    /**
     * Resizes that image by defining a new height by keeping ratio.
     */
    resizeHeight(newHeight: number): IBitmap;

    /**
     * Resizes that image by defining a new (maximum) size by keeping ratio.
     */
    resizeMax(maxSize: number): IBitmap;

    /**
     * Resizes that image by defining a new width by keeping ratio.
     */
    resizeWidth(newWidth: number): IBitmap;

    /**
     * Rotates the image.
     */
    rotate(degrees?: number): IBitmap;

    /**
     * Sets a pixel / point.
     */
    setPoint(coordinates?: IPoint2D | string,
             color?: string | number | IArgb): IBitmap;

    /**
     * Gets the size.
     */
    size: ISize;

    /**
     * Converts that image to a Base64 string.
     */
    toBase64(format?: OutputFormat, quality?: number): string;

    /**
     * Converts that image to a data URL.
     */
    toDataUrl(format?: OutputFormat, quality?: number): string;

    /**
     * Returns that image as ImageSource.
     */
    toImageSource(): ImageSource;

    /**
     * Converts that image to an object.
     */
    toObject(format?: OutputFormat, quality?: number): IBitmapData;

    /**
     * Writes a text.
     */
    writeText(txt: any,
              leftTop?: IPoint2D | string, font?: IFont | string): IBitmap;

    /**
     * Gets the width of the bitmap.
     */
    width: number;
}

Contributors

• Dimitar Topuzov
• Geoff Bullen
• Jonathan Salomon
• Josh Huckabee