Yet another 2D API abstraction
kcanvas is easy to use C++ API for rendering 2D graphics. Its main purpose is to make 2D graphics programming easier and hide nasty details of platform specific graphics APIs. It's crossplatform and has native implementation for supported platforms (Direct2D on windows, Quartz on Mac OS X, Cairo on Linux). It's suitable for rendering 2D graphics such as user interfaces, data visualization, diagrams and other text and visual content. It's not intended to be used in interactive games, however simple 2D game could be rendered with kcanvas API.
This project is under development now, so not all of its features are implemented and
not all platforms are fully supported
Windows demo and examples binaries
kcanvas API is able to render 2D vector and raster graphics. You can stroke and fill different simple and complex shapes with many different styles, render text with different fonts available in your system. Here is sample image which shows what you can render with help of kcanvas API:
Features
- Commonly used predefined shapes (line, bezier, arc, rectangle, rounded rectangle, ellipse, poly lines and polygons)
- Shapes of arbitrary complexity
- Many different line stroke styles, line join styles
- Several fill styles (solid, linear and radial gradients, bitmap)
- Full alpha transparency support
- Clipping to shapes and masking by grayscale images, mask fill with brush
- Bitmap rendering (with alpha channel support)
- Arbitrary transformation stack (via 3x2 matrix)
- Text measurement and rendering (with simple layouts)
Ongoing development
The Roadmap wiki page contains some
information about current project status and ongoing feature support and development plans.
In kcanvas API all of painting functions tied to kCanvas class. kCanvas object can't be
instantiated directly, you need to use specific implementation to direct painting to specific
device or kBitmap object. You can use kContextCanvas to paint into window and
kBitmapCanvas to paint into kBitmap object.
Most of the properties for painting operation are taken from special resource objects, in general
kcanvas API is stateless with few exceptions. Resource objects are immutable – once created their
properties can't be changed. Some of resource objects can't be copied (kBitmap and
kGradient) and always remains unique.
kStrokeobject holds properties for line style. It defines line pattern, line join style and line caps style.kGradientobject holds color gradient definition.kPenobject holds properties for stroke (outline painting) operations, it incapsulateskStrokeandkBrushobjects.kBrushobject holds properties for fill operations.kFontobject holds font properties for text painting (and measuring).kPathobject holds geometric shape data.kBitmapobject holds raster image data.
See reference wiki pages for full
kcanvas API types and classes reference.
See guide wiki page for general kcanvas
concepts and usage.
Under the hood kcanvas API uses one of existing platform specific APIs, such as Direct2D on Windows platform.
Having proper setup
of your project for using kcanvas library (correct path to kcanvas include directory and
kcanvas library linked into project) you only need to include kcanvas/canvas.h header in
your source to get all kcanvas API stuff. To paint something you need to instantiate
kContextCanvas object and issue painting commands.
Here is quick "Hello world" example:
// DeviceContext is platform dependent context descriptor,
// such as HDC or CGContextRef
kContextCanvas canvas(DeviceContext);
// create some resource objects for painting
// orange solid pen, 4 pixels wide
kPen pen(kColor(255, 127, 39), 4);
// yellow solid brush
kBrush brush(kColor(255, 201, 14));
// black solid brush
kBrush black(kColor::Black);
// font
kFont font("Tahoma", 50, kFontStyle::Bold);
// text to paint
const char *text = "Hello world!";
// measure text to find out rectangle which can include this text
kSize textsize = canvas.TextSize(text, -1, font);
// paint rectangle with outline
canvas.Rectangle(kRect(kPoint(10), textsize + 20), &pen, &brush);
// paint text
canvas.Text(kPoint(20, 20), text, -1, font, black);Result:
Please visit examples wiki page for additional information and usage examples.
Please visit guide wiki page for build instructions.
kcanvas 2D Graphics Library
Copyright (C) 2015 – 2017, livingcreative (https://github.com/livingcreative)
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