path.textureBounds

Type Table
Object Path
Library display.*
Revision Release 2021.3646
Keywords texture, bounds

Overview

A read-only table with properties uMin, uMax, vMin, vMax that represent the boundaries of the display object's texture being referenced. Some shaders, for instance, might use this to establish a local coordinate system.

The values are normalized from 0 to 1 (versus pixels as in image sheets). A display object that is neither a mesh nor uses an image will have minimum and maximum values of 0 and 1, respectively.

Example

local tex = graphics.newTexture{ type = "canvas", width = 128, height = 128 }
local back = display.newRect(0, 0, 128, 128)

back:setFillColor(1, 0, 0)

local rect = display.newRect(0, 0, 32, 64)

rect:setFillColor(0, 0, 1)

tex:draw(back)
tex:draw(rect)
tex:invalidate()

local fill = { type = "image", filename = tex.filename, baseDir = tex.baseDir }

local function Bounds (object)
    local bounds = object.path.textureBounds

    return "Bounds: uMin = " .. bounds.uMin .. ", vMin = " .. bounds.vMin .. ", uMax = " .. bounds.uMax .. ", vMax = " .. bounds.vMax
end

local vanilla = display.newRect(50, 50, 30, 30)

vanilla.fill = fill

print("VANILLA RECT")
print(Bounds(vanilla))
print("")

local polygon = display.newPolygon(150, 120, { 0, -110, 27, -35, 105, -35, 43, 16, 65, 90, 0, 45, -65, 90, -43, 15, -105, -35, -27, -35, })

polygon.fill = fill

print("STAR POLYGON")
print(Bounds(polygon))
print("")

local mesh = display.newMesh{
    x = 300, y = 100,
    mode = "triangles",
    vertices = {
        -5, 0, 90, 0, 0, 100,
        0, 100, 90, 0, 130, 100,
        130, 100, 90, 0, 100, 0
    },
    uvs = {
        0, 0, 0.25, 0, 0, .9,
        0, .9, 0.25, 0, 1, .75,
        1, .75, 0.25, 0, 1, 0
    }
}

mesh:translate(mesh.path:getVertexOffset())  -- Translate mesh so that vertices have proper world coordinates
 
mesh.fill = fill

print("MESH")
print(Bounds(mesh))
print("")

local options = {
    frames = {
        {
            x = 64 - 16,
            y = 64 - 32,
            width = 32,
            height = 64
        }
    }
}

local sheet = graphics.newImageSheet(tex.filename, tex.baseDir, options)
local image = display.newImage(sheet, 1)

image.x, image.y = 500, 100

print("SHEET-BASED IMAGE")
print(Bounds(image))
print("")

local sprite = display.newSprite(sheet, { name = "state", start = 1, count = 1 })

sprite.x, sprite.y = 600, 150

print("SPRITE FRAME")
print(Bounds(sprite))