366 lines
9.8 KiB
Nim
366 lines
9.8 KiB
Nim
|
## Load and Save SVG files.
|
||
|
|
|
||
|
|
import chroma, pixie/images, pixie/common, pixie/paths, vmath, xmlparser,
|
||
|
|
xmltree, strutils, strutils, cairo
|
||
|
|
|
||
|
|
type Path = paths.Path
|
||
|
|
|
||
|
|
proc processCommands(c: ptr Context, path: paths.Path) =
|
||
|
|
c.newPath()
|
||
|
|
c.moveTo(0, 0)
|
||
|
|
for i, command in path.commands:
|
||
|
|
case command.kind
|
||
|
|
of Move:
|
||
|
|
c.moveTo(command.numbers[0], command.numbers[1])
|
||
|
|
of Line:
|
||
|
|
c.lineTo(command.numbers[0], command.numbers[1])
|
||
|
|
of HLine:
|
||
|
|
echo "HLine not yet supported for Cairo"
|
||
|
|
of VLine:
|
||
|
|
echo "VLine not yet supported for Cairo"
|
||
|
|
of Cubic:
|
||
|
|
c.curveTo(
|
||
|
|
command.numbers[0],
|
||
|
|
command.numbers[1],
|
||
|
|
command.numbers[2],
|
||
|
|
command.numbers[3],
|
||
|
|
command.numbers[4],
|
||
|
|
command.numbers[5]
|
||
|
|
)
|
||
|
|
of SCubic:
|
||
|
|
echo "SCubic not yet supported for Cairo"
|
||
|
|
of Quad:
|
||
|
|
echo "Quad not supported by Cairo"
|
||
|
|
of TQuad:
|
||
|
|
echo "TQuad not supported by Cairo"
|
||
|
|
of Arc:
|
||
|
|
echo "Arc not yet supported for Cairo"
|
||
|
|
of RMove:
|
||
|
|
c.relMoveTo(command.numbers[0], command.numbers[1])
|
||
|
|
of RLine:
|
||
|
|
c.relLineTo(command.numbers[0], command.numbers[1])
|
||
|
|
of RHLine:
|
||
|
|
c.relLineTo(command.numbers[0], 0)
|
||
|
|
of RVLine:
|
||
|
|
c.relLineTo(0, command.numbers[0])
|
||
|
|
of RCubic:
|
||
|
|
c.relCurveTo(
|
||
|
|
command.numbers[0],
|
||
|
|
command.numbers[1],
|
||
|
|
command.numbers[2],
|
||
|
|
command.numbers[3],
|
||
|
|
command.numbers[4],
|
||
|
|
command.numbers[5]
|
||
|
|
)
|
||
|
|
of RSCubic:
|
||
|
|
# This is not correct but good enough for now
|
||
|
|
c.relLineTo(
|
||
|
|
command.numbers[2],
|
||
|
|
command.numbers[3]
|
||
|
|
)
|
||
|
|
of RQuad:
|
||
|
|
echo "RQuad not supported by Cairo"
|
||
|
|
of RTQuad:
|
||
|
|
echo "RTQuad not supported by Cairo"
|
||
|
|
of RArc:
|
||
|
|
echo "RArc not yet supported for Cairo"
|
||
|
|
of Close:
|
||
|
|
c.closePath()
|
||
|
|
|
||
|
|
checkStatus(c.status())
|
||
|
|
|
||
|
|
proc prepare(
|
||
|
|
c: ptr Context,
|
||
|
|
path: Path,
|
||
|
|
color: ColorRGBA,
|
||
|
|
mat: Mat3
|
||
|
|
) =
|
||
|
|
let
|
||
|
|
color = color.color()
|
||
|
|
matrix = Matrix(
|
||
|
|
xx: mat[0, 0],
|
||
|
|
yx: mat[0, 1],
|
||
|
|
xy: mat[1, 0],
|
||
|
|
yy: mat[1, 1],
|
||
|
|
x0: mat[2, 0],
|
||
|
|
y0: mat[2, 1],
|
||
|
|
)
|
||
|
|
c.setSourceRgba(color.r, color.g, color.b, color.a)
|
||
|
|
c.setMatrix(matrix.unsafeAddr)
|
||
|
|
c.processCommands(path)
|
||
|
|
|
||
|
|
proc fillPath(
|
||
|
|
c: ptr Context,
|
||
|
|
path: Path,
|
||
|
|
color: ColorRGBA,
|
||
|
|
mat: Mat3
|
||
|
|
) =
|
||
|
|
prepare(c, path, color, mat)
|
||
|
|
c.fill()
|
||
|
|
|
||
|
|
proc strokePath(
|
||
|
|
c: ptr Context,
|
||
|
|
path: Path,
|
||
|
|
color: ColorRGBA,
|
||
|
|
strokeWidth: float32,
|
||
|
|
mat: Mat3
|
||
|
|
) =
|
||
|
|
prepare(c, path, color, mat)
|
||
|
|
c.setLineWidth(strokeWidth)
|
||
|
|
c.stroke()
|
||
|
|
|
||
|
|
const svgSignature* = "<?xml"
|
||
|
|
|
||
|
|
type Ctx = object
|
||
|
|
fill, stroke: ColorRGBA
|
||
|
|
strokeWidth: float32
|
||
|
|
transform: Mat3
|
||
|
|
|
||
|
|
when defined(pixieTestCairo):
|
||
|
|
type RenderTarget = ptr Context
|
||
|
|
else:
|
||
|
|
type RenderTarget = Image
|
||
|
|
|
||
|
|
template failInvalid() =
|
||
|
|
raise newException(PixieError, "Invalid SVG data")
|
||
|
|
|
||
|
|
proc initCtx(): Ctx =
|
||
|
|
result.fill = parseHtmlColor("black").rgba.toPremultipliedAlpha()
|
||
|
|
result.strokeWidth = 1
|
||
|
|
result.transform = mat3()
|
||
|
|
|
||
|
|
proc decodeCtx(inherited: Ctx, node: XmlNode): Ctx =
|
||
|
|
result = inherited
|
||
|
|
|
||
|
|
let
|
||
|
|
fill = node.attr("fill")
|
||
|
|
stroke = node.attr("stroke")
|
||
|
|
strokeWidth = node.attr("stroke-width")
|
||
|
|
transform = node.attr("transform")
|
||
|
|
|
||
|
|
if fill == "":
|
||
|
|
discard # Inherit
|
||
|
|
elif fill == "none":
|
||
|
|
result.fill = ColorRGBA()
|
||
|
|
else:
|
||
|
|
result.fill = parseHtmlColor(fill).rgba.toPremultipliedAlpha()
|
||
|
|
|
||
|
|
if stroke == "":
|
||
|
|
discard # Inherit
|
||
|
|
elif stroke == "none":
|
||
|
|
result.stroke = ColorRGBA()
|
||
|
|
else:
|
||
|
|
result.stroke = parseHtmlColor(stroke).rgba.toPremultipliedAlpha()
|
||
|
|
|
||
|
|
if strokeWidth == "":
|
||
|
|
discard # Inherit
|
||
|
|
else:
|
||
|
|
result.strokeWidth = parseFloat(strokeWidth)
|
||
|
|
|
||
|
|
if transform == "":
|
||
|
|
discard # Inherit
|
||
|
|
else:
|
||
|
|
template failInvalidTransform(transform: string) =
|
||
|
|
raise newException(
|
||
|
|
PixieError, "Unsupported SVG transform: " & transform & "."
|
||
|
|
)
|
||
|
|
|
||
|
|
var remaining = transform
|
||
|
|
while remaining.len > 0:
|
||
|
|
let index = remaining.find(")")
|
||
|
|
if index == -1:
|
||
|
|
failInvalidTransform(transform)
|
||
|
|
let f = remaining[0 .. index].strip()
|
||
|
|
remaining = remaining[index + 1 .. ^1]
|
||
|
|
|
||
|
|
if f.startsWith("matrix("):
|
||
|
|
let arr = f[7 .. ^2].split(",")
|
||
|
|
if arr.len != 6:
|
||
|
|
failInvalidTransform(transform)
|
||
|
|
var m = mat3()
|
||
|
|
m[0] = parseFloat(arr[0])
|
||
|
|
m[1] = parseFloat(arr[1])
|
||
|
|
m[3] = parseFloat(arr[2])
|
||
|
|
m[4] = parseFloat(arr[3])
|
||
|
|
m[6] = parseFloat(arr[4])
|
||
|
|
m[7] = parseFloat(arr[5])
|
||
|
|
result.transform = result.transform * m
|
||
|
|
elif f.startsWith("translate("):
|
||
|
|
let
|
||
|
|
components = f[10 .. ^2].split(" ")
|
||
|
|
tx = parseFloat(components[0])
|
||
|
|
ty = parseFloat(components[1])
|
||
|
|
result.transform = result.transform * translate(vec2(tx, ty))
|
||
|
|
elif f.startsWith("rotate("):
|
||
|
|
let angle = parseFloat(f[7 .. ^2]) * -PI / 180
|
||
|
|
result.transform = result.transform * rotationMat3(angle)
|
||
|
|
else:
|
||
|
|
failInvalidTransform(transform)
|
||
|
|
|
||
|
|
proc draw(
|
||
|
|
img: ptr Context, node: XmlNode, ctxStack: var seq[Ctx]
|
||
|
|
) =
|
||
|
|
if node.kind != xnElement:
|
||
|
|
# Skip <!-- comments -->
|
||
|
|
return
|
||
|
|
|
||
|
|
case node.tag:
|
||
|
|
of "title", "desc":
|
||
|
|
discard
|
||
|
|
|
||
|
|
of "g":
|
||
|
|
let ctx = decodeCtx(ctxStack[^1], node)
|
||
|
|
ctxStack.add(ctx)
|
||
|
|
for child in node:
|
||
|
|
img.draw(child, ctxStack)
|
||
|
|
discard ctxStack.pop()
|
||
|
|
|
||
|
|
of "path":
|
||
|
|
let
|
||
|
|
d = node.attr("d")
|
||
|
|
ctx = decodeCtx(ctxStack[^1], node)
|
||
|
|
path = parsePath(d)
|
||
|
|
if ctx.fill != ColorRGBA():
|
||
|
|
img.fillPath(path, ctx.fill, ctx.transform)
|
||
|
|
if ctx.stroke != ColorRGBA() and ctx.strokeWidth > 0:
|
||
|
|
img.strokePath(path, ctx.stroke, ctx.strokeWidth, ctx.transform)
|
||
|
|
|
||
|
|
of "line":
|
||
|
|
let
|
||
|
|
ctx = decodeCtx(ctxStack[^1], node)
|
||
|
|
x1 = parseFloat(node.attr("x1"))
|
||
|
|
y1 = parseFloat(node.attr("y1"))
|
||
|
|
x2 = parseFloat(node.attr("x2"))
|
||
|
|
y2 = parseFloat(node.attr("y2"))
|
||
|
|
|
||
|
|
var path: Path
|
||
|
|
path.moveTo(x1, y1)
|
||
|
|
path.lineTo(x2, y2)
|
||
|
|
path.closePath()
|
||
|
|
|
||
|
|
if ctx.fill != ColorRGBA():
|
||
|
|
img.fillPath(path, ctx.fill, ctx.transform)
|
||
|
|
if ctx.stroke != ColorRGBA() and ctx.strokeWidth > 0:
|
||
|
|
img.strokePath(path, ctx.stroke, ctx.strokeWidth, ctx.transform)
|
||
|
|
|
||
|
|
of "polyline", "polygon":
|
||
|
|
let
|
||
|
|
ctx = decodeCtx(ctxStack[^1], node)
|
||
|
|
points = node.attr("points")
|
||
|
|
|
||
|
|
var vecs: seq[Vec2]
|
||
|
|
for pair in points.split(" "):
|
||
|
|
let parts = pair.split(",")
|
||
|
|
if parts.len != 2:
|
||
|
|
failInvalid()
|
||
|
|
vecs.add(vec2(parseFloat(parts[0]), parseFloat(parts[1])))
|
||
|
|
|
||
|
|
if vecs.len == 0:
|
||
|
|
failInvalid()
|
||
|
|
|
||
|
|
var path: Path
|
||
|
|
path.moveTo(vecs[0])
|
||
|
|
for i in 1 ..< vecs.len:
|
||
|
|
path.lineTo(vecs[i])
|
||
|
|
|
||
|
|
# The difference between polyline and polygon is whether we close the path
|
||
|
|
if node.tag == "polygon":
|
||
|
|
path.closePath()
|
||
|
|
|
||
|
|
if ctx.fill != ColorRGBA():
|
||
|
|
img.fillPath(path, ctx.fill, ctx.transform)
|
||
|
|
if ctx.stroke != ColorRGBA() and ctx.strokeWidth > 0:
|
||
|
|
img.strokePath(path, ctx.stroke, ctx.strokeWidth, ctx.transform)
|
||
|
|
|
||
|
|
of "rect":
|
||
|
|
let
|
||
|
|
ctx = decodeCtx(ctxStack[^1], node)
|
||
|
|
x = parseFloat(node.attr("x"))
|
||
|
|
y = parseFloat(node.attr("y"))
|
||
|
|
width = parseFloat(node.attr("width"))
|
||
|
|
height = parseFloat(node.attr("height"))
|
||
|
|
|
||
|
|
var path: Path
|
||
|
|
path.rect(x, y, width, height)
|
||
|
|
|
||
|
|
if ctx.fill != ColorRGBA():
|
||
|
|
img.fillPath(path, ctx.fill, ctx.transform)
|
||
|
|
if ctx.stroke != ColorRGBA() and ctx.strokeWidth > 0:
|
||
|
|
img.strokePath(path, ctx.stroke, ctx.strokeWidth, ctx.transform)
|
||
|
|
|
||
|
|
of "circle", "ellipse":
|
||
|
|
# Reference for magic constant:
|
||
|
|
# https://dl3.pushbulletusercontent.com/a3fLVC8boTzRoxevD1OgCzRzERB9z2EZ/unknown.png
|
||
|
|
let ctx = decodeCtx(ctxStack[^1], node)
|
||
|
|
|
||
|
|
var cx, cy: float32 # Default to 0.0 unless set by cx and cy on node
|
||
|
|
if node.attr("cx") != "":
|
||
|
|
cx = parseFloat(node.attr("cx"))
|
||
|
|
if node.attr("cy") != "":
|
||
|
|
cy = parseFloat(node.attr("cy"))
|
||
|
|
|
||
|
|
var rx, ry: float32
|
||
|
|
if node.tag == "circle":
|
||
|
|
rx = parseFloat(node.attr("r"))
|
||
|
|
ry = rx
|
||
|
|
else:
|
||
|
|
rx = parseFloat(node.attr("rx"))
|
||
|
|
ry = parseFloat(node.attr("ry"))
|
||
|
|
|
||
|
|
let
|
||
|
|
magicX = (4.0 * (-1.0 + sqrt(2.0)) / 3) * rx
|
||
|
|
magicY = (4.0 * (-1.0 + sqrt(2.0)) / 3) * ry
|
||
|
|
|
||
|
|
var path: Path
|
||
|
|
path.moveTo(cx + rx, cy)
|
||
|
|
path.bezierCurveTo(cx + rx, cy + magicY, cx + magicX, cy + ry, cx, cy + ry)
|
||
|
|
path.bezierCurveTo(cx - magicX, cy + ry, cx - rx, cy + magicY, cx - rx, cy)
|
||
|
|
path.bezierCurveTo(cx - rx, cy - magicY, cx - magicX, cy - ry, cx, cy - ry)
|
||
|
|
path.bezierCurveTo(cx + magicX, cy - ry, cx + rx, cy - magicY, cx + rx, cy)
|
||
|
|
path.closePath()
|
||
|
|
|
||
|
|
if ctx.fill != ColorRGBA():
|
||
|
|
img.fillPath(path, ctx.fill, ctx.transform)
|
||
|
|
if ctx.stroke != ColorRGBA() and ctx.strokeWidth > 0:
|
||
|
|
img.strokePath(path, ctx.stroke, ctx.strokeWidth, ctx.transform)
|
||
|
|
|
||
|
|
else:
|
||
|
|
raise newException(PixieError, "Unsupported SVG tag: " & node.tag & ".")
|
||
|
|
|
||
|
|
proc decodeSvg*(data: string): Image =
|
||
|
|
## Render SVG file and return the image.
|
||
|
|
try:
|
||
|
|
let root = parseXml(data)
|
||
|
|
if root.tag != "svg":
|
||
|
|
failInvalid()
|
||
|
|
|
||
|
|
let
|
||
|
|
viewBox = root.attr("viewBox")
|
||
|
|
box = viewBox.split(" ")
|
||
|
|
if parseInt(box[0]) != 0 or parseInt(box[1]) != 0:
|
||
|
|
failInvalid()
|
||
|
|
|
||
|
|
let
|
||
|
|
width = parseInt(box[2])
|
||
|
|
height = parseInt(box[3])
|
||
|
|
var ctxStack = @[initCtx()]
|
||
|
|
result = newImage(width, height)
|
||
|
|
let
|
||
|
|
surface = imageSurfaceCreate(FORMAT_ARGB32, width.int32, height.int32)
|
||
|
|
c = surface.create()
|
||
|
|
for node in root:
|
||
|
|
c.draw(node, ctxStack)
|
||
|
|
surface.flush()
|
||
|
|
let pixels = cast[ptr UncheckedArray[array[4, uint8]]](surface.getData())
|
||
|
|
for y in 0 ..< result.height:
|
||
|
|
for x in 0 ..< result.width:
|
||
|
|
let
|
||
|
|
bgra = pixels[result.dataIndex(x, y)]
|
||
|
|
rgba = rgba(bgra[2], bgra[1], bgra[0], bgra[3])
|
||
|
|
result.setRgbaUnsafe(x, y, rgba)
|
||
|
|
result.toStraightAlpha()
|
||
|
|
except PixieError as e:
|
||
|
|
raise e
|
||
|
|
except:
|
||
|
|
raise newException(PixieError, "Unable to load SVG")
|