Line/Square Tool, Undo Feature, and Linked Doodad Lines #11

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kirsle · 2019-07-01T22:32:53Z

kirsle commented

2019-07-01 22:32:53 +00:00

This describes an idea how to support a Line and Rectangle drawing tool, the Undo feature, and ability to draw "imaginary" connecting lines to visualize linked Doodads.

// Stroke represents one atomic drawing element. It is used as a
// "staging" object when actively dragging a new shape onto a level,
// a "unit of work" for the Undo/Redo feature, and a holder for
// arbitrary temporary lines such as to visualize Doodad links,
// collision hitbox debug lines, etc.
type Stroke struct {
    Shape int  // Freehand, Line, Square
    Color render.Color

    // Lines and Squares have only two important points
    Point1 render.Point  // start point
    Point2 render.Point  // stop/current point

    // Freehand lines record all of their points
    Points []render.Point
}

Freehand Tool

On mouse down, create a new Stroke and begin logging every pixel intended for change as the user drags the mouse around.
On release, commit the Stroke's points to the drawing all at once.

Line and Square Tool

On mouse down, create a new Stroke and record the first point clicked as Point1.
On drag, update Point2 to the current point under the cursor.
On release, commit the shape to the level drawing.

Undo/Redo Feature

Store an array of Strokes into a History buffer and have a HistoryIndex pointing to the current/most recent stroke.
On Undo, roll the HistoryIndex back and undo the strokes that came after, etc.

Doodad Link Lines

When the Doodad Tool or Link Tool is active, loop through all the actors to find their links.
For every given pair of actors A and B, create a Stroke object that draws a Line between the center of actor A and the center of actor B.

This describes an idea how to support a Line and Rectangle drawing tool, the Undo feature, and ability to draw "imaginary" connecting lines to visualize linked Doodads. ```go // Stroke represents one atomic drawing element. It is used as a // "staging" object when actively dragging a new shape onto a level, // a "unit of work" for the Undo/Redo feature, and a holder for // arbitrary temporary lines such as to visualize Doodad links, // collision hitbox debug lines, etc. type Stroke struct { Shape int // Freehand, Line, Square Color render.Color // Lines and Squares have only two important points Point1 render.Point // start point Point2 render.Point // stop/current point // Freehand lines record all of their points Points []render.Point } ``` ## Freehand Tool * On mouse down, create a new Stroke and begin logging every pixel intended for change as the user drags the mouse around. * On release, commit the Stroke's points to the drawing all at once. ## Line and Square Tool * On mouse down, create a new Stroke and record the first point clicked as Point1. * On drag, update Point2 to the current point under the cursor. * On release, commit the shape to the level drawing. ## Undo/Redo Feature * Store an array of Strokes into a History buffer and have a HistoryIndex pointing to the current/most recent stroke. * On Undo, roll the HistoryIndex back and undo the strokes that came after, etc. ## Doodad Link Lines * When the Doodad Tool or Link Tool is active, loop through all the actors to find their links. * For every given pair of actors A and B, create a Stroke object that draws a Line between the center of actor A and the center of actor B.

kirsle added this to the First Beta Release MVP milestone 2019-07-05 23:29:42 +00:00

kirsle closed this issue

2019-07-05 23:29:50 +00:00

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