Copyright (C) 2008 ~ 2025 Zhang Ji Peng (onecoolx@gmail.com)

Picasso is a high quality vector graphic rendering library. It has high performance and low footprint. Picasso provides a set of high level 2D graphics API, which can be used to a GUI system, rendering postscript, rendering svg images and so on. It support path, matrix, gradient, pattern, image and truetype font.

Features

• Path Filling, Stroking
• Solid Color, Gradient, Pattern
• Stroke Dashing
• Linecap Butt, Round, Square
• Linejoin Miter, Round, Bevel
• Transform and Matrix
• Filling Rule
• Blur
• Shadow
• Clipping
• Compisiting
• Font and Text
• Image Decoders jpeg, png, webp, gif
• SVG Tiny 1.2
• SVG Animation

How to build

linux:

1. Install cmake above v3.16 on your system
 $ sudo apt install cmake

2. Build project
 ./build_linux.sh
 cd proj
 make

windows:

1. Install cmake above v3.16 on your windows system and register path environment variables.
 c:\> winget install --id Kitware.CMake -e

2. Build project
 build_windows.bat
 cd proj
 <open "picasso.sln" with visual studio>

macosx:

1. Install cmake above v3.16 on your system
 $ brew install cmake

2. Build project
 ./build_macosx.sh
 cd proj
 <open "picasso.xcodeproj" with Xcode>

Quick Start

The following example creates an off-screen canvas, draws a filled rectangle with a radial gradient, and saves the result. It demonstrates the core Picasso workflow: canvas → context → draw → release.

#include "picasso.h"

int main(void)
{
    /* 1. Initialize the library */
    ps_initialize();

    /* 2. Allocate a pixel buffer and create a canvas backed by it */
    int width = 400, height = 300;
    int stride = width * 4;                          /* RGBA8888: 4 bytes per pixel */
    unsigned char* buf = (unsigned char*)malloc(stride * height);
    memset(buf, 0, stride * height);

    ps_canvas* canvas = ps_canvas_create_with_data(buf, COLOR_FORMAT_RGBA,
                                                   width, height, stride);

    /* 3. Create a drawing context */
    ps_context* ctx = ps_context_create(canvas, NULL);

    /* 4. Build a radial gradient */
    ps_point center = { 200.0f, 150.0f };
    ps_gradient* grad = ps_gradient_create_radial(GRADIENT_SPREAD_PAD,
                                                  &center, 0.0f,
                                                  &center, 180.0f);
    ps_color c0 = { 0.2f, 0.6f, 1.0f, 1.0f };   /* light blue  */
    ps_color c1 = { 0.0f, 0.1f, 0.4f, 1.0f };   /* dark blue   */
    ps_gradient_add_color_stop(grad, 0.0f, &c0);
    ps_gradient_add_color_stop(grad, 1.0f, &c1);

    /* 5. Draw a rounded rectangle filled with the gradient */
    ps_rect rc = { 40.0f, 30.0f, 320.0f, 240.0f };
    ps_rounded_rect(ctx, &rc, 16, 16, 16, 16, 16, 16, 16, 16);
    ps_set_source_gradient(ctx, grad);
    ps_fill(ctx);

    /* 6. Stroke a border */
    ps_color stroke = { 1.0f, 1.0f, 1.0f, 0.8f };
    ps_set_stroke_color(ctx, &stroke);
    ps_set_line_width(ctx, 2.0f);
    ps_rounded_rect(ctx, &rc, 16, 16, 16, 16, 16, 16, 16, 16);
    ps_stroke(ctx);

    /* 7. Release resources */
    ps_gradient_unref(grad);
    ps_context_unref(ctx);
    ps_canvas_unref(canvas);
    free(buf);

    ps_shutdown();
    return 0;
}

The pixel buffer buf now contains the rendered RGBA image and can be passed to any display or image-encoding layer.

Documents

API Reference Documents

Gallery

Alpha Blending & Compositing	SVG Rendering
Alpha blending across multiple overlapping geometry shapes	Full SVG path, gradient, and stroke rendering (Tiger benchmark)

GIS / Map Rendering	Realtime Instrumentation
High-density polyline and label rendering for GIS applications	Arc, gradient, and affine transform compositing for realtime UI