Module ui.geometry
Utilities for 2D geometry.
All of these apply to full rectangles:
local Geom = require("ui/geometry") Geom:new{ x = 1, y = 0, w = Screen:scaleBySize(100), h = Screen:scaleBySize(200), }
Some behaviour is defined for points:
Geom:new{ x = 0, y = 0, }
Some behaviour is defined for dimensions:
Geom:new{ w = Screen:scaleBySize(600), h = Screen:scaleBySize(800), }
Just use it on simple tables that have x, y and/or w, h or define your own types using this as a metatable.
Where BlitBuffer is concerned, a point at (0, 0) means the top-left corner.
Functions
| Geom:copy () | Makes a deep copy of itself. |
| Geom:offsetBy (dx, dy) | Offsets rectangle or point by relative values |
| Geom:offsetTo (x, y) | Offsets rectangle or point to certain coordinates |
| Geom:scaleBy (zx, zy) | Scales rectangle (top-left corner is rounded down, bottom-right corner is rounded up) or dimension |
| Geom:transformByScale (zx, zy) |
This method also takes care of x and y on top of Geom:scaleBy, c.f., fzroundrect in MµPDF, |
| Geom:area () | Returns area of itself. |
| Geom:changeSizeBy (dw, dh) | Enlarges or shrinks dimensions or rectangles |
| Geom:combine (rect_b) | Returns a new outer rectangle that contains both us and a given rectangle |
| Geom:intersect (rect_b) | Returns a new rectangle for the part that we and a given rectangle share |
| Geom:notIntersectWith (rect_b) | Returns true if self does not share any area or edge with rect_b |
| Geom:intersectWith (rect_b) | Returns true if self geom shares area with rect_b. |
| Geom:notOpenIntersectWith (rect_b) | Returns true if self does not share any area with rect_b |
| Geom:openIntersectWith (rect_b) | Returns true if self geom shares area or an edge with rect_b. |
| Geom:setSizeTo (rect_b) | Set size of dimension or rectangle to size of given dimension/rectangle. |
| Geom:contains (geom) | Checks whether geom is within current rectangle
Works for dimensions, too. |
| Geom:__eq (rect_b) | Checks for equality. |
| Geom:equalSize (rect_b) | Checks the size of a dimension/rectangle for equality. |
| Geom:__lt (rect_b) | Checks if our size is smaller than the size of the given dimension/rectangle. |
| Geom:__le (rect_b) | Checks if our size is smaller or equal to the size of the given dimension/rectangle. |
| Geom:offsetWithin (rect_b, dx, dy) | Offsets the current rectangle by dx, dy while fitting it into the space of a given rectangle. |
| Geom:centerWithin (rect_b, dx, dy) | Centers the current rectangle at position x and y of a given rectangle. |
| Geom:distance (rect_b) | Returns the Euclidean distance between two geoms. |
| Geom:midpoint (geom) | Returns the midpoint of two geoms. |
| Geom:center () | Returns the center point of this geom. |
| Geom:clear () | Resets an existing Geom object to zero. |
| Geom:isEmpty () | Checks if a dimension or rectangle is empty. |
| Geom.boundingBox (rectangles) | Returns a bounding box which encompasses all passed rectangles. |
Tables
| Geom | Represents a full rectangle (all fields are set), a point (x & y are set), or a dimension (w & h are set). |
Functions
- Geom:copy ()
-
Makes a deep copy of itself.
Returns:
- Geom:offsetBy (dx, dy)
-
Offsets rectangle or point by relative values
Parameters:
- dx integer x delta
- dy integer y delta
- Geom:offsetTo (x, y)
-
Offsets rectangle or point to certain coordinates
Parameters:
- x integer new x
- y integer new y
- Geom:scaleBy (zx, zy)
-
Scales rectangle (top-left corner is rounded down, bottom-right corner is rounded up) or dimension If a single factor is given, it is applied to both width and height
Parameters:
- zx integer scale for x axis
- zy integer scale for y axis
- Geom:transformByScale (zx, zy)
-
This method also takes care of x and y on top of Geom:scaleBy, c.f., fzroundrect in MµPDF,
<https://github.com/ArtifexSoftware/mupdf/blob/d00de0e96a4a5ec90ffc30837d40cd624a6a89e0/source/fitz/geometry.c#L400-L416>Parameters:
- zx integer scale for x axis
- zy integer scale for y axis
- Geom:area ()
-
Returns area of itself.
Returns:
-
int
- Geom:changeSizeBy (dw, dh)
-
Enlarges or shrinks dimensions or rectangles Note that for rectangles the offset stays the same
Parameters:
- dw integer width delta
- dh integer height delta
- Geom:combine (rect_b)
-
Returns a new outer rectangle that contains both us and a given rectangle Works for rectangles, dimensions and points
Parameters:
- rect_b Geom
Returns:
- Geom:intersect (rect_b)
-
Returns a new rectangle for the part that we and a given rectangle share
Parameters:
- rect_b Geom
Returns:
- Geom:notIntersectWith (rect_b)
-
Returns true if self does not share any area or edge with rect_b
Parameters:
- rect_b Geom
- Geom:intersectWith (rect_b)
-
Returns true if self geom shares area with rect_b.
Parameters:
- rect_b Geom
- Geom:notOpenIntersectWith (rect_b)
-
Returns true if self does not share any area with rect_b
Parameters:
- rect_b Geom
- Geom:openIntersectWith (rect_b)
-
Returns true if self geom shares area or an edge with rect_b.
Parameters:
- rect_b Geom
- Geom:setSizeTo (rect_b)
-
Set size of dimension or rectangle to size of given dimension/rectangle.
Parameters:
- rect_b Geom
- Geom:contains (geom)
-
Checks whether geom is within current rectangle
Works for dimensions, too. For points, it is basically an equality check.
Parameters:
- geom Geom
- Geom:__eq (rect_b)
-
Checks for equality.
Works for rectangles, points, and dimensions.
Parameters:
- rect_b Geom
- Geom:equalSize (rect_b)
-
Checks the size of a dimension/rectangle for equality.
Parameters:
- rect_b Geom
- Geom:__lt (rect_b)
-
Checks if our size is smaller than the size of the given dimension/rectangle.
Parameters:
- rect_b Geom
- Geom:__le (rect_b)
-
Checks if our size is smaller or equal to the size of the given dimension/rectangle.
Parameters:
- rect_b Geom
- Geom:offsetWithin (rect_b, dx, dy)
-
Offsets the current rectangle by dx, dy while fitting it into the space
of a given rectangle.
This can also be called with dx=0 and dy=0, which will fit the current rectangle into the given rectangle.
Parameters:
- rect_b Geom
- dx integer
- dy integer
- Geom:centerWithin (rect_b, dx, dy)
-
Centers the current rectangle at position x and y of a given rectangle.
Parameters:
- rect_b Geom
- dx integer
- dy integer
- Geom:distance (rect_b)
-
Returns the Euclidean distance between two geoms.
Parameters:
- rect_b Geom
- Geom:midpoint (geom)
-
Returns the midpoint of two geoms.
Parameters:
- geom Geom
Returns:
- Geom:center ()
-
Returns the center point of this geom.
Returns:
- Geom:clear ()
-
Resets an existing Geom object to zero.
Returns:
- Geom:isEmpty ()
-
Checks if a dimension or rectangle is empty.
Returns:
-
bool
- Geom.boundingBox (rectangles)
-
Returns a bounding box which encompasses all passed rectangles.
Parameters:
- rectangles Geom to encompass
Returns:
-
Geom
bounding box or nil if no rectangles passed