# libcairo **Repository Path**: mirrors_edadma/libcairo ## Basic Information - **Project Name**: libcairo - **Description**: Scala Native bindings for the Cairo 2D graphics library - **Primary Language**: Unknown - **License**: ISC - **Default Branch**: main - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2023-02-28 - **Last Updated**: 2026-04-13 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README libcairo ======== ![GitHub release (latest by date including pre-releases)](https://img.shields.io/github/v/release/edadma/libcairo?include_prereleases) ![GitHub (Pre-)Release Date](https://img.shields.io/github/release-date-pre/edadma/libcairo) ![GitHub last commit](https://img.shields.io/github/last-commit/edadma/libcairo) ![GitHub](https://img.shields.io/github/license/edadma/libcairo) *libcairo* provides Scala Native bindings for the [Cairo](https://www.cairographics.org/) 2D graphics C library. Overview -------- The goal of this project is to provide an easy-to-use Scala Native facade for the entire Cairo 2D graphics library. Currently, many of the basic functions needed to do graphics, and to read and write PNGs are covered. The remainder of the library will be steadily worked on. The more "programmer friendly" part of this library is found in the `io.github.edadma.libcairo` package. That's the only package you need to import from, as seen in the example below. The other package in the library is `io.github.edadma.libcairo.extern` which provides for interaction with the *libcairo* C library using Scala Native interoperability elements from the so-call `unsafe` namespace. There are no public declarations in the `io.github.edadma.libcairo` package that use `unsafe` types in their parameter or return types, making it a pure Scala facade. Consequently, you never have to worry about memory allocation or type conversions. Usage ----- To use this library, `libcairo2-dev` needs to be installed: ```shell sudo apt install libcairo2-dev ``` Include the following in your `project/plugins.sbt`: ```sbt addSbtPlugin("com.codecommit" % "sbt-github-packages" % "0.5.3") ``` Include the following in your `build.sbt`: ```sbt resolvers += Resolver.githubPackages("edadma") libraryDependencies += "io.github.edadma" %%% "libcairo" % "0.1.5" ``` Use the following `import` in your code: ```scala import io.github.edadma.libcairo._ ``` Examples -------- The following examples are direct translations of examples from the Cairo documentation, specifically their [tutorial](https://www.cairographics.org/tutorial/#L1drawing). ### Example 1 This example creates a PNG file called `setsourcergba.png` containing the following image: ![setsourcergba](https://raw.githubusercontent.com/edadma/libcairo/main/setsourcergba.png) ```scala import io.github.edadma.libcairo._ @main def run(): Unit = val surface = imageSurfaceCreate(Format.ARGB32, 120, 120) val cr = surface.create cr.scale(120, 120) cr.setSourceRGB(0, 0, 0) cr.moveTo(0, 0) cr.lineTo(1, 1) cr.moveTo(1, 0) cr.lineTo(0, 1) cr.setLineWidth(0.2) cr.stroke() cr.rectangle(0, 0, 0.5, 0.5) cr.setSourceRGBA(1, 0, 0, 0.80) cr.fill() cr.rectangle(0, 0.5, 0.5, 0.5) cr.setSourceRGBA(0, 1, 0, 0.60) cr.fill() cr.rectangle(0.5, 0, 0.5, 0.5) cr.setSourceRGBA(0, 0, 1, 0.40) cr.fill() surface.writeToPNG("setsourcergba.png") cr.destroy() surface.destroy() ``` ### Example 2 This example creates a PNG file called `setsourcegradient.png` containing the following image: ![setsourcegradient](https://raw.githubusercontent.com/edadma/libcairo/main/setsourcegradient.png) ```scala import io.github.edadma.libcairo._ @main def run(): Unit = val surface = imageSurfaceCreate(Format.ARGB32, 120, 120) val cr = surface.create /* Examples are in 1.0 x 1.0 coordinate space */ cr.scale(120, 120) val radpat = patternCreateRadial(0.25, 0.25, 0.1, 0.5, 0.5, 0.5) radpat.addColorStopRGB(0, 1.0, 0.8, 0.8) radpat.addColorStopRGB(1, 0.9, 0.0, 0.0) for i <- 1 to 9; j <- 1 to 9 do cr.rectangle(i / 10.0 - 0.04, j / 10.0 - 0.04, 0.08, 0.08) cr.setSource(radpat) cr.fill() val linpat = patternCreateLinear(0.25, 0.35, 0.75, 0.65) linpat.addColorStopRGBA(0.00, 1, 1, 1, 0) linpat.addColorStopRGBA(0.25, 0, 1, 0, 0.5) linpat.addColorStopRGBA(0.50, 1, 1, 1, 0) linpat.addColorStopRGBA(0.75, 0, 0, 1, 0.5) linpat.addColorStopRGBA(1.00, 1, 1, 1, 0) cr.rectangle(0.0, 0.0, 1, 1) cr.setSource(linpat) cr.fill() surface.writeToPNG("setsourcegradient.png") cr.destroy() surface.destroy() ``` ### Example 3 This example creates a PNG file called `path-close.png` containing the following image (may not be clearly visible if your Github is in dark mode): ![path-close](https://raw.githubusercontent.com/edadma/libcairo/main/path-close.png) ```scala import math._ import io.github.edadma.libcairo._ @main def run(): Unit = val surface = imageSurfaceCreate(Format.ARGB32, 120, 120) val cr = surface.create cr.scale(120, 120) cr.setLineWidth(0.1) cr.setSourceRGB(0, 0, 0) cr.moveTo(0.25, 0.25) cr.lineTo(0.5, 0.375) cr.relLineTo(0.25, -0.125) cr.arc(0.5, 0.5, 0.25 * sqrt(2), -0.25 * Pi, 0.25 * Pi) cr.relCurveTo(-0.25, -0.125, -0.25, 0.125, -0.5, 0) cr.closePath() cr.stroke() surface.writeToPNG("path-close.png") cr.destroy() surface.destroy() ``` ### Example 4 This example creates a PNG file called `textextents.png` containing the following image (may not be clearly visible if your Github is in dark mode): ![textextents](https://raw.githubusercontent.com/edadma/libcairo/main/textextents.png) ```scala import math._ import io.github.edadma.libcairo._ @main def run(): Unit = /* Prepare drawing area */ val surface = imageSurfaceCreate(Format.ARGB32, 240, 240) val cr = surface.create /* Example is in 26.0 x 1.0 coordinate space */ cr.scale(240, 240) cr.setFontSize(0.5) /* Drawing code goes here */ cr.setSourceRGB(0.0, 0.0, 0.0) cr.selectFontFace("Georgia", FontSlant.NORMAL, FontWeight.BOLD) val fe = cr.fontExtents val (ux, uy) = cr.deviceToUserDistance(1, 1) val px = max(ux, uy) val text = "joy" val te = cr.textExtents(text) val x = 0.5 - te.xBearing - te.width / 2 val y = 0.5 - fe.descent + fe.height / 2 /* baseline, descent, ascent, height */ cr.setLineWidth(4 * px) cr.setDash(Seq(9 * px), 0) cr.setSourceRGBA(0, 0.6, 0, 0.5) cr.moveTo(x + te.xBearing, y) cr.relLineTo(te.width, 0) cr.moveTo(x + te.xBearing, y + fe.descent) cr.relLineTo(te.width, 0) cr.moveTo(x + te.xBearing, y - fe.ascent) cr.relLineTo(te.width, 0) cr.moveTo(x + te.xBearing, y - fe.height) cr.relLineTo(te.width, 0) cr.stroke() /* extents: width & height */ cr.setSourceRGBA(0, 0, 0.75, 0.5) cr.setLineWidth(px) cr.setDash(Seq(3 * px), 0) cr.rectangle(x + te.xBearing, y + te.yBearing, te.width, te.height) cr.stroke() /* text */ cr.moveTo(x, y) cr.setSourceRGB(0, 0, 0) cr.showText(text) /* bearing */ cr.setDash(Nil, 0) cr.setLineWidth(2 * px) cr.setSourceRGBA(0, 0, 0.75, 0.5) cr.moveTo(x, y) cr.relLineTo(te.xBearing, te.yBearing) cr.stroke() /* text's advance */ cr.setSourceRGBA(0, 0, 0.75, 0.5) cr.arc(x + te.xAdvance, y + te.yAdvance, 5 * px, 0, 2 * Pi) cr.fill() /* reference point */ cr.arc(x, y, 5 * px, 0, 2 * Pi) cr.setSourceRGBA(0.75, 0, 0, 0.5) cr.fill() /* Write output and clean up */ surface.writeToPNG("textextents.png") cr.destroy() surface.destroy() ``` Documentation ------------- API documentation is forthcoming, however documentation for the C library is found [here](https://www.cairographics.org/documentation/). License ------- [ISC](https://github.com/edadma/libcairo/blob/main/LICENSE)