slack-gif-creator Checked

**Pay attention to colors**:

• Use vibrant, complementary colors
• Add contrast (dark outlines on light shapes, light outlines on dark shapes)
• Consider the overall composition

**For complex shapes** (hearts, snowflakes, etc.):

• Use combinations of polygons and ellipses
• Calculate points carefully for symmetry
• Add details (a heart can have a highlight curve, snowflakes have intricate branches)

Be creative and detailed! A good Slack GIF should look polished, not like placeholder graphics.

Available Utilities

### GIFBuilder (core.gif_builder)

Assembles frames and optimizes for Slack:

builder = GIFBuilder(width=128, height=128, fps=10)
builder.add_frame(frame)  # Add PIL Image
builder.add_frames(frames)  # Add list of frames
builder.save('out.gif', num_colors=48, optimize_for_emoji=True, remove_duplicates=True)

### Validators (core.validators)

Check if GIF meets Slack requirements:

from core.validators import validate_gif, is_slack_ready

# Detailed validation
passes, info = validate_gif('my.gif', is_emoji=True, verbose=True)

# Quick check
if is_slack_ready('my.gif'):
    print("Ready!")

### Easing Functions (core.easing)

Smooth motion instead of linear:

from core.easing import interpolate

# Progress from 0.0 to 1.0
t = i / (num_frames - 1)

# Apply easing
y = interpolate(start=0, end=400, t=t, easing='ease_out')

# Available: linear, ease_in, ease_out, ease_in_out,
#           bounce_out, elastic_out, back_out

### Frame Helpers (core.frame_composer)

Convenience functions for common needs:

from core.frame_composer import (
    create_blank_frame,         # Solid color background
    create_gradient_background,  # Vertical gradient
    draw_circle,                # Helper for circles
    draw_text,                  # Simple text rendering
    draw_star                   # 5-pointed star
)

Animation Concepts

### Shake/Vibrate

Offset object position with oscillation:

• Use math.sin() or math.cos() with frame index
• Add small random variations for natural feel
• Apply to x and/or y position

### Pulse/Heartbeat

Scale object size rhythmically:

• Use math.sin(t * frequency * 2 * math.pi) for smooth pulse
• For heartbeat: two quick pulses then pause (adjust sine wave)
• Scale between 0.8 and 1.2 of base size

### Bounce

Object falls and bounces:

• Use interpolate() with easing='bounce_out' for landing
• Use easing='ease_in' for falling (accelerating)
• Apply gravity by increasing y velocity each frame

### Spin/Rotate

Rotate object around center:

• PIL: image.rotate(angle, resample=Image.BICUBIC)
• For wobble: use sine wave for angle instead of linear

### Fade In/Out

Gradually appear or disappear:

• Create RGBA image, adjust alpha channel
• Or use Image.blend(image1, image2, alpha)
• Fade in: alpha from 0 to 1
• Fade out: alpha from 1 to 0

### Slide

Move object from off-screen to position:

• Start position: outside frame bounds
• End position: target location
• Use interpolate() with easing='ease_out' for smooth stop
• For overshoot: use easing='back_out'

### Zoom

Scale and position for zoom effect:

• Zoom in: scale from 0.1 to 2.0, crop center
• Zoom out: scale from 2.0 to 1.0
• Can add motion blur for drama (PIL filter)

### Explode/Particle Burst

Create particles radiating outward:

• Generate particles with random angles and velocities
• Update each particle: x += vx, y += vy
• Add gravity: vy += gravity_constant
• Fade out particles over time (reduce alpha)

Optimization Strategies

Only when asked to make the file size smaller, implement a few of the following methods:

1. **Fewer frames** - Lower FPS (10 instead of 20) or shorter duration

2. **Fewer colors** - num_colors=48 instead of 128

3. **Smaller dimensions** - 128x128 instead of 480x480

4. **Remove duplicates** - remove_duplicates=True in save()

5. **Emoji mode** - optimize_for_emoji=True auto-optimizes

# Maximum optimization for emoji
builder.save(
    'emoji.gif',
    num_colors=48,
    optimize_for_emoji=True,
    remove_duplicates=True
)

Philosophy

This skill provides:

• **Knowledge**: Slack's requirements and animation concepts
• **Utilities**: GIFBuilder, validators, easing functions
• **Flexibility**: Create the animation logic using PIL primitives

It does NOT provide:

• Rigid animation templates or pre-made functions
• Emoji font rendering (unreliable across platforms)
• A library of pre-packaged graphics built into the skill

**Note on user uploads**: This skill doesn't include pre-built graphics, but if a user uploads an image, use PIL to load and work with it - interpret based on their request whether they want it used directly or just as inspiration.

Be creative! Combine concepts (bouncing + rotating, pulsing + sliding, etc.) and use PIL's full capabilities.

Dependencies

pip install pillow imageio numpy