adding canvas guide

This commit is contained in:
Robert Jelic
2025-04-25 21:54:28 +02:00
parent 2f750e2836
commit 179949c8b7
3 changed files with 129 additions and 5 deletions

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@@ -65,6 +65,7 @@ export default defineConfig({
{ text: 'Annotations', link: '/guides/annotations' },
{ text: 'Animations', link: '/guides/animations' },
{ text: 'Benchmark', link: '/guides/benchmarks' },
{ text: 'Canvas', link: 'guides/canvas'},
{ text: 'Properties', link: '/guides/properties' },
{ text: 'States', link: '/guides/states' },
{ text: 'XML', link: '/guides/xml' },
@@ -113,7 +114,7 @@ export default defineConfig({
{text: 'Table', link: 'references/elements/Table'},
{text: 'TextBox', link: 'references/elements/TextBox'},
{text: 'Tree', link: 'references/elements/Tree'},
{text: 'Timer', link: 'references/elements/Timer'},
//{text: 'Timer', link: 'references/elements/Timer'},
{text: 'ScrollBar', link: 'references/elements/ScrollBar'},
{text: 'Slider', link: 'references/elements/Slider'},
{text: 'ProgressBar', link: 'references/elements/ProgressBar'},

126
docs/guides/canvas.md Normal file
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@@ -0,0 +1,126 @@
# Canvas Plugin Guide
The Canvas plugin allows you to draw various shapes and text on your elements. It provides a simple yet powerful way to create custom graphics.
## Basic Usage
First, you need to get the canvas object:
```lua
local main = basalt.createFrame()
local canvas = main:getCanvas()
```
## Drawing Functions
### Lines
Draw a line from point (x1,y1) to (x2,y2):
```lua
canvas:line(1, 1, 10, 10, "*", colors.red, colors.black) -- Draws a red line
```
### Rectangles
Create rectangles with specified dimensions:
```lua
canvas:rect(5, 5, 10, 5, "#", colors.blue, colors.white) -- Creates a blue rectangle
```
### Ellipses
Draw ellipses/circles:
```lua
canvas:ellipse(10, 10, 5, 3, "@", colors.green, colors.black) -- Creates an ellipse
```
### Text
Write text at specific coordinates:
```lua
canvas:text(1, 1, "Hello World!", colors.yellow, colors.black)
```
## Color Management
### Background Colors
Set background color at specific coordinates:
```lua
canvas:bg(1, 1, colors.blue)
```
### Foreground Colors
Set foreground color at specific coordinates:
```lua
canvas:fg(1, 1, colors.white)
```
## Render Types
The canvas plugin supports two different render types that control when the canvas commands are executed:
### Setting the Render Type
```lua
canvas:setType(type)
```
Parameters:
- `type`: String, either "pre" or "post"
- `"pre"`: Commands are executed before the main object rendering (default)
- `"post"`: Commands are executed after the main object rendering
Example:
```lua
-- Create a canvas that renders after the main object
local canvas = main:addCanvas()
canvas:setType("post")
-- Add commands that will now execute after main rendering
canvas:addCommand(function()
canvas:drawText(1, 1, "Overlay Text")
end)
-- or
canvas:line(1, 1, 10, 10, " ", colors.red, colors.green)
```
Note: Changing the render type affects all subsequent commands added to the canvas. You can have multiple canvas objects with different render types on the same base object.
## Canvas Commands
Canvas commands allow you to create custom drawing operations using low-level drawing functions. Available commands are:
- `textFg` - Set text foreground color
- `textBg` - Set text background color
- `drawText` - Draw text
- `drawFg` - Draw foreground colors
- `drawBg` - Draw background colors
- `blit` - Draw text with foreground and background colors
- `multiBlit` - Draw multiple blit operations
### Adding Commands
```lua
-- Example of proper command usage
canvas:addCommand(function()
-- Draw red text on black background
canvas:drawText(1, 1, "Hello")
canvas:drawFg(1, 1, colors.red)
canvas:drawBg(1, 1, colors.black)
-- Or use blit for more efficient drawing
canvas:blit(1, 2, "Hello", "fffff", "00000") -- white on black
end)
```
### Advanced Blit Example
The multiBlit function allows you to render text efficiently in a rectangular area:
```lua
canvas:addCommand(function()
-- Parameters: x, y, width, height, text, fg, bg
canvas:multiBlit(1, 1, 5, 3,
"HelloWorld!Hello", -- text (width * height characters)
"ffffffffff", -- fg colors (width * height characters)
"0000000000" -- bg colors (width * height characters)
)
end)
```
Note: Do not use drawing functions like `line`, `rect`, or `ellipse` inside commands as this will cause render queue issues. Use the low-level drawing functions instead.

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@@ -72,9 +72,6 @@ export {};
'__ctx' extends keyof __VLS_PickNotAny<K, {}> ? K extends { __ctx?: infer Ctx } ? Ctx : never : any
, T extends (props: any, ctx: infer Ctx) => any ? Ctx : any
>>;
type __VLS_OmitStringIndex<T> = {
[K in keyof T as string extends K ? never : K]: T[K];
};
type __VLS_UseTemplateRef<T> = Readonly<import('vue').ShallowRef<T | null>>;
function __VLS_getVForSourceType<T extends number | string | any[] | Iterable<any>>(source: T): [
@@ -116,6 +113,6 @@ export {};
: (_: {} & Record<string, unknown>, ctx?: any) => { __ctx?: { attrs?: any, expose?: any, slots?: any, emit?: any, props?: {} & Record<string, unknown> } };
function __VLS_functionalComponentArgsRest<T extends (...args: any) => any>(t: T): 2 extends Parameters<T>['length'] ? [any] : [];
function __VLS_asFunctionalElement<T>(tag: T, endTag?: T): (attrs: T & Record<string, unknown>) => void;
function __VLS_asFunctionalSlot<S>(slot: S): (props: NonNullable<S> extends (props: infer P) => any ? P : {}) => void;
function __VLS_asFunctionalSlot<S>(slot: S): S extends () => infer R ? (props: {}) => R : NonNullable<S>;
function __VLS_tryAsConstant<const T>(t: T): T;
}