Thor

A Finagle-based image processor.

NOTE: JDK7 or higher required. Run java -version and check that it shows at least 1.7.

Installation

1. Clone the repo: git clone https://github.com/rdio/thor.git
2. Add your application.conf to src/main/resources and configure a media host (see reference.conf for default properties or https://github.com/typesafehub/config/ for more documentation)
3. Run the app: sbt run
4. Navigate to a valid relative path on your media provider http://localhost:8080/?l=my_img.jpg to verify that its working

Querystring Params

• w - width of the final image
• h - height of the final image
• c - compression quality to apply to jpeg image results (0-100)
• f - file format; one of: png or jpeg (default)
• l - <layer>[; <layer>]+ - a sequence of one or more layers separated by a semi-colon: ;
  • layer - <source>[:<filter>]|<filter> - a layer consists of a single image source and an optional filter separated by a colon: :, or a single filter without a source
    • source - <url>|$<index>|_ - either a relative url path or a layer reference or an empty layer. NOTE: An incorrect source will log and fail silently, returning the image as far as processed.
      • url - any relative url accessible by the media provider
      • layer reference - $<index> - zero-based index into any preceeding layer
      • empty layer — _ - a blank layer the size of the final output with pixels initialized to fully transparent
    • filter - <filter-name>([args]) - filter to apply to the current layer or if no source was provided, the previous layer
      • linear gradient - linear(<angle>, <color-stop>, <color-stop> [, <color-stop>]+) - applies a linear gradient over the layer at <angle> degrees with at least two color stops
        • color stop - <rgb|rgba> <percentage>% - supports either rgb or rgba colors
      • blur - blur() - blurs the image using a 3x3 convolution kernel
      • fit - fit() - resizes the layer to the request dimensions so that it is the maximum possible size while maintaining aspect ratio
      • cover - cover() - resizes the layer to the request dimensions so that it is the minimum size needed without leaving any background visible
      • text - text("{{text}}", font, <rgb|rgba>) - draws the specified text over the center of the image
      • text (positioned) - text("{{text}}", font, color, imagePosition|[imagePosition], hAlign, vAlign, fit)
      • frame - `frame(length, color)
      • boxblur - boxblur(<horizontal-radius>px, <vertical-radius>px)|boxblur(<horizontal-radius>%, <vertical-radius>%) - applies a box blur to the image by horizontal-radius and vertical-radius
      • scale - scale(<percent>%) - resizes the image by percent
      • scaleto - scaleto(<width-pixels>, <height-pixels>) - resizes the image to the specified dimensions
      • grid - grid(<source>[, <source>]+) - forms a grid from the list of source images (original layer included in the grid)
      • round - round(<radius-pixels>px|<radius-percent>%) - rounds the corners of the layer by radius-pixels
      • pad - pad(<padding-pixels>px|<padding-percent>%) - applies padding around the image by padding-pixels
      • colorize - colorize(<color>) - overlays the specified color over the image
      • overlay - overlay(<source>) - overlays the specified source over the image
      • mask - mask(<overlay-source>, <mask-source>) - blends between the layer and overlay-source using mask-source as a guide, where white in the mask reveals the overlay and black reveals the layer
    • other things:
      • string :=
      • length := pixels | percent | percentWidth | percentHeight
      • hAlign := "left" | "center" | "right"
      • vAlign := "top" | "center" | "bottom"
      • imagePosition := "centered" | cartesian(percent, percent) | cartesian(pixels, pixels)
      • fit := fromContent|fitted(width: pixels, maxFontSize: int)
      • font := font-style size font-name
        • font-style := "normal" | "bold" | "italic"
        • font-name := string where the font must be installed locally or copied as a .ttf into the resources folder
      • size := pixels | percent
      • pixels := "{{number}}px"
      • percent := "{{number}}%"
      • color := rgb | rgba | hsl | hsla
      • rgb := rgb(<r>, <g>, <b>) — specifies a color with values between 0.0-1.0.
      • rgba := rgba(<r>, <g>, <b>, <a>)
      • hsl := hsl(<h>, <s>, <l>) - specifies a color with hsl, h with values between 0.0-360.0, and s and l with values between 0.0-1.0.
      • hsla := hsla(<h>, <s>, <l>, <a>)

Examples

(all querystring params have been url encoded, e.g. encodeURIComponent in javascript)

• http://localhost:8080/?l=img_a.jpg%3Bboxblur(40px%2C40px)
  • Blurs img_a.jpg using a 40x40 box blur
• http://localhost:8080/?l=img_a.jpg%3Bimg_b.jpg%3B_%3Alinear(0deg%2C%20rgba(0%2C%200%2C%200%2C%200)%200%25%2C%20rgba(0%2C%200%2C%200%2C%201)%20100%25)%3B%240%3Amask(%241%2C%20%242)
  • Linearly interpolates between two images (img_a.jpg and img_b.jpg) using a linear gradient as a blending mask. Layers:
    1. img_a.jpg
    2. img_b.jpg
    3. _:linear(0deg, rgba(0, 0, 0, 0) 0%, rgba(0, 0, 0, 1) 100%) # on an empty layer, create a linear gradient that fades from fully transparent black to fully opaque black
    4. $0:mask($1, $2) # Blend between layers $0 and $1 using layer $2 as a mask
• http://localhost:8080/l=img_a.jpg;$0:frame(16px,rgba(0,0,0,0.75));$1:text("Dooh dee dooh", bold italic 36px "Helvetica", rgb(0.75,0.25,0.25), [cartesian(9%,75%), cartesian(0px,4px)], left, top, fitted(75%,36px))
  • draws a frame on the image, and draws some text on the image, fitted so that it doesn't exceed 75% of the width:
    

License

Copyright 2014 Rdio, Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.