Visual Design

What this skill does

# Visual Design for Presentations

Effective visual design combines diagrams, images, and consistent theming to create engaging, professional, accessible presentations. Master mermaid diagrams, stock photography, AI image generation, colorblind-safe palettes, and visual cohesion.

**Evidence-based accessibility**: This skill incorporates research-based best practices for accessible visual design. See `references/presentation-best-practices.md` for full guidelines.

## Mermaid Diagrams

Mermaid provides text-based diagramming that renders beautifully in Slidev and exports well.

### Flowcharts

Best for: Processes, decision trees, workflows

**Basic syntax:**
```mermaid
graph TD
    A[Start] --> B{Decision}
    B -->|Yes| C[Action 1]
    B -->|No| D[Action 2]
    C --> E[End]
    D --> E
```

**Direction options:**
- `graph TD` - Top to bottom
- `graph LR` - Left to right
- `graph RL` - Right to left
- `graph BT` - Bottom to top

**Node shapes:**
```mermaid
graph LR
    A[Rectangle]
    B(Rounded)
    C([Stadium])
    D[[Subroutine]]
    E[(Database)]
    F((Circle))
    G>Flag]
    H{Diamond}
    I{{Hexagon}}
```

**Arrow types:**
```mermaid
graph LR
    A-->B      %% Solid arrow
    C-.->D     %% Dotted arrow
    E==>F      %% Thick arrow
    G-.-H      %% Dotted line
    I---J      %% Solid line
```

**Edge labels:**
```mermaid
graph LR
    A -->|Label text| B
    B -.->|Another label| C
```

### Sequence Diagrams

Best for: API calls, interactions, communication flows

```mermaid
sequenceDiagram
    participant Client
    participant Server
    participant Database

    Client->>Server: HTTP Request
    Server->>Database: Query
    Database-->>Server: Results
    Server-->>Client: HTTP Response
```

**Message types:**
- `->` Solid line
- `-->` Dotted line
- `->>` Solid arrow
- `-->>` Dotted arrow

**Activation boxes:**
```mermaid
sequenceDiagram
    Client->>+Server: Request
    Server->>+Database: Query
    Database-->>-Server: Data
    Server-->>-Client: Response
```

**Notes:**
```mermaid
sequenceDiagram
    Client->>Server: Request
    Note right of Server: Processing
    Server->>Database: Query
    Note over Client,Server: Communication
```

### Class Diagrams

Best for: Object-oriented design, data models, architecture

```mermaid
classDiagram
    class User {
        +String name
        +String email
        +login()
        +logout()
    }

    class Order {
        +int orderId
        +Date date
        +calculateTotal()
    }

    User "1" --> "*" Order : places
```

**Relationships:**
- `<|--` Inheritance
- `*--` Composition
- `o--` Aggregation
- `-->` Association
- `--` Link
- `..|>` Realization
- `..` Dependency

**Visibility:**
- `+` Public
- `-` Private
- `#` Protected
- `~` Package

### State Diagrams

Best for: State machines, lifecycle, status changes

```mermaid
stateDiagram-v2
    [*] --> Draft
    Draft --> Review
    Review --> Approved
    Review --> Rejected
    Rejected --> Draft
    Approved --> Published
    Published --> [*]
```

**With descriptions:**
```mermaid
stateDiagram-v2
    [*] --> Idle
    Idle --> Processing : Start
    Processing --> Complete : Success
    Processing --> Error : Failure
    Error --> Idle : Retry
    Complete --> [*]
```

### ER Diagrams

Best for: Database schemas, data relationships

```mermaid
erDiagram
    CUSTOMER ||--o{ ORDER : places
    ORDER ||--|{ LINE-ITEM : contains
    PRODUCT ||--o{ LINE-ITEM : includes

    CUSTOMER {
        string name
        string email
        int customerId
    }

    ORDER {
        int orderId
        date orderDate
        float total
    }
```

**Relationship types:**
- `||--||` One to one
- `||--o{` One to many
- `}o--o{` Many to many
- `||--o|` Zero or one

### Gantt Charts

Best for: Timelines, project schedules, roadmaps

```mermaid
gantt
    title Project Timeline
    dateFormat YYYY-MM-DD

    section Phase 1
    Task 1           :a1, 2024-01-01, 30d
    Task 2           :after a1, 20d

    section Phase 2
    Task 3           :2024-02-01, 25d
    Task 4           :2024-02-15, 20d
```

### Theming Diagrams

Apply consistent colors:

```mermaid
%%{init: {'theme':'base', 'themeVariables': {
  'primaryColor':'#3b82f6',
  'primaryTextColor':'#fff',
  'primaryBorderColor':'#2563eb',
  'lineColor':'#6b7280',
  'secondaryColor':'#8b5cf6',
  'tertiaryColor':'#f59e0b'
}}}%%
graph TD
    A[Start] --> B[Process]
    B --> C[End]
```

**Theme presets:**
- `default` - Standard colors
- `dark` - Dark mode
- `forest` - Green tones
- `neutral` - Grayscale
- `base` - Customizable (use themeVariables)

## Diagram Selection Guide

**Process or workflow?** → Flowchart
- Shows steps and decisions
- Linear or branching paths
- Start and end points clear

**System interaction?** → Sequence Diagram
- Shows communication between components
- Time-ordered messages
- Request/response patterns

**Data structure?** → Class or ER Diagram
- Shows entities and relationships
- Object-oriented design
- Database schema

**State changes?** → State Diagram
- Shows status transitions
- Lifecycle representation
- Finite states

**Timeline or schedule?** → Gantt Chart
- Shows tasks over time
- Dependencies and milestones
- Project planning

**Complex architecture?** → Component + Flowchart
- Multiple diagram types
- Different abstraction levels
- Layered view

## Stock Photography

### Image Selection Criteria

**Relevance:**
- Directly related to slide content
- Reinforces message
- Doesn't distract

**Quality:**
- Minimum 1920x1080 resolution
- Sharp, well-lit
- Professional composition

**Tone:**
- Matches presentation style
- Appropriate for audience
- Consistent emotional impact

**Diversity:**
- Inclusive representation
- Varied perspectives
- Authentic, not staged

### Unsplash Search Strategies

**Concept-based searches:**
- "team collaboration"
- "data visualization"
- "technology innovation"
- "business meeting"
- "cloud computing abstract"

**Color-specific searches:**
- "blue technology"
- "minimal white background"
- "dark professional"

**Orientation searches:**
- Add "landscape" for 16:9 slides
- Add "portrait" for split layouts

**Quality indicators:**
- High view count
- Professional photographer
- Editorial collection

### Pexels Alternative

Similar to Unsplash, good backup source:
- Free for commercial use
- No attribution required (but appreciated)
- Good for videos too

### Attribution

Include in presenter notes or final slide:

```markdown
<!--
Image credits:
- Photo by [Photographer Name] on Unsplash
- https://unsplash.com/photos/[photo-id]
-->
```

### Image Optimization

**Before using:**
- Resize to 1920x1080 maximum
- Compress to reduce file size
- Save in appropriate format (JPG for photos, PNG for graphics)

**Tools:**
- ImageMagick: `convert input.jpg -resize 1920x1080 output.jpg`
- Online: TinyPNG, Squoosh

## AI Image Generation

### DALL-E 3 Prompting

**Structure:**
```
[Subject] + [Style] + [Composition] + [Colors] + [Details] + [Quality]
```

**Examples:**

Technical presentation:
```
Isometric illustration of cloud infrastructure, interconnected servers
and databases, modern tech style, blue and purple gradient, clean
minimal design, high detail, professional quality
```

Business presentation:
```
Professional photograph of diverse business team in modern office,
collaborating around laptop, natural lighting, corporate environment,
blue and gray tones, shallow depth of field, high resolution
```

Data visualization:
```
Abstract data visualization, flowing connections and nodes,
information network concept, gradient from blue to cyan,
dark background, glowing elements, futuristic style, 16:9 ratio
```

**Best practices:**
- Be specific about style (photo, illustration, 3D render)
- Specify aspect ratio (16:9 for slides)
- Include lighting details for realism
- Mention color palette for consistency
- Add quality descriptors (high detail, professional)

### Midjourney Prompting

**Structure:**
```
/imagine [description] --ar 16:9 --v 6 --s