Brapi

A UI rendering library for Fabric mods. Supports rounded rectangles, text, gradients, textures, and 9-slice sprites with a simple API. With future support for SVG rasterizer, shadows, more text options, toggleable immediate mode rendering and lines.

Why

Making good-looking UIs in Minecraft is harder than it should be. Vanilla's tools work fine for basic boxes, but as soon as you want smooth rounded corners, circles, or nice-looking text, you hit a wall. Normally you're stuck with two options:

1. Bring in a heavy graphics library like Skia, which is hard to set-up for first time
2. Write your own shaders from scratch, which means dealing with extra setup and boilerplate most modders would rather skip

Brapi gives a third option. It's a lightweight layer that sits on top of Minecraft's existing rendering system, so you get the nice visuals without the pain. Key Benefits:

• Zero Boilerplate: No setup hassle. Just create a BRender, add your draw calls, and flush.
• Complex Shapes Made Simple: Draw circles, outlines, and rounded rectangles (even with different corner sizes) in a single line of code.
• Automatic Batching & Layering: Brapi figures out the right draw order on its own, so your UI looks right without you micromanaging it.

📦 Setup

Adding as dependency

Add the repository and dependency to build.gradle:

repositories {
    exclusiveContent {
        forRepository {
            maven {
                name = "Modrinth"
                url = "https://api.modrinth.com/maven"
            }
        }
        filter {
            includeGroup "maven.modrinth"
        }
    }
}
dependencies {
    modImplementation "maven.modrinth:brapi:0.25.3+${minecraft_version}+fabric" // only supported minecraft version is 1.21.11 right now
}

fabric.mod.json:

"depends": {
    "brapi": "*"
}

Using in code

Create a BRender instance, add draw calls, then call flush(graphics) to submit. Everything renders at end of frame sorted by layer.

🎨 All colors are ARGB: 0xFFFF0000 = opaque red, 0x80FF0000 = 50% transparent red.
📐 Coordinates are in GuiScale units: (100, 100) at scale 3 = (300, 300) pixels.

Filled shapes

• bRender.rect(100, 100, 100, 100, 0xFFFF0000, layer); - red 100x100 rectangle
• bRender.roundRect(100, 100, 100, 100, 0xFFFF0000, 10, layer); - rounded rectangle, 10px radius
• bRender.roundRect(100, 100, 100, 100, 0xFFFF0000, 10, 5, layer); - 10px TL/BR, 5px TR/BL radius
• bRender.roundRect(100, 100, 100, 100, 0xFFFF0000, 10, 5, 20, 30, layer); - individual corner radii
• bRender.circle(100, 100, 50, 0xFFFF0000, layer); - circle, 50px radius

Gradients

All filled shapes support gradients via Gradient and GradientDirection:

• bRender.roundRect(100, 100, 100, 100, gradient, GradientDirection.LEFT_RIGHT, 10, layer);

Directions: LEFT_RIGHT, TOP_BOTTOM, TOP_LEFT_BOTTOM_RIGHT, TOP_RIGHT_BOTTOM_LEFT

Strokes (outline only)

• bRender.stroke(100, 100, 100, 100, 0xFFFF0000, 2, layer); - 2px outline rectangle
• bRender.strokeRounded(100, 100, 100, 100, 0xFFFF0000, 10, 2, layer); - 2px rounded outline, 10px radius
• bRender.strokeRounded(100, 100, 100, 100, 0xFFFF0000, 10, 5, 2, layer); - 10px TL/BR, 5px TR/BL
• bRender.strokeRounded(100, 100, 100, 100, 0xFFFF0000, 10, 5, 20, 30, 2, layer); - individual radii

Filled + stroke

• bRender.roundRectStroked(100, 100, 100, 100, 0xFF0000FF, 0xFFFF0000, 10, 2, layer); - blue fill, 2px red stroke

Text

• bRender.drawText(font, "Hello!", 100, 100, 24, 0xFFFFFFFF, layer); - BFont text
• bRender.drawText(font, formattedCharSequence, 100, 100, 24, 0xFFFFFFFF, layer); - formatted text with per-character colors

Textures

• bRender.drawTexture(tex, 100, 100, 200, 150, 0xFFFFFFFF, linear, layer); - stretch to fill
• bRender.drawTextureCropped(tex, 100, 100, 64, 64, 0, 0, 32, 32, 0xFFFFFFFF, linear, layer); - crop
• bRender.drawTextureTiled(tex, 100, 100, 200, 200, 0xFFFFFFFF, linear, layer); - tile
• bRender.drawTexture9Slice(slice, 100, 100, 300, 200, 0xFFFFFFFF, linear, layer); - 9-slice

🔄 Flushing

BRender r = new BRender();
r.roundRect(...);
r.flush(graphics); // submit to draw list