From 40dfcfcde109b36481d3c5b90cc7a9246905928b Mon Sep 17 00:00:00 2001
From: Ryan Oldenburg <guzba8@gmail.com>
Date: Sat, 23 Jan 2021 21:15:39 -0600
Subject: [PATCH] 0.0.16 quadraticCurveTo, transform

---
 pixie.nimble        |  2 +-
 src/pixie/paths.nim | 70 +++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 68 insertions(+), 4 deletions(-)

diff --git a/pixie.nimble b/pixie.nimble
index 6f0215f..ed00d2d 100644
--- a/pixie.nimble
+++ b/pixie.nimble
@@ -1,4 +1,4 @@
-version     = "0.0.15"
+version     = "0.0.16"
 author      = "Andre von Houck and Ryan Oldenburg"
 description = "Full-featured 2d graphics library for Nim."
 license     = "MIT"
diff --git a/src/pixie/paths.nim b/src/pixie/paths.nim
index 9925ca8..89a7572 100644
--- a/src/pixie/paths.nim
+++ b/src/pixie/paths.nim
@@ -188,6 +188,60 @@ proc `$`*(path: Path): string =
       if i != path.commands.len - 1 or j != command.numbers.len - 1:
         result.add " "
 
+proc transform*(path: Path, mat: Mat3) =
+  for command in path.commands.mitems:
+    case command.kind:
+    of Close:
+      discard
+    of Move, Line, RMove, RLine, TQuad, RTQuad:
+      var pos = vec2(command.numbers[0], command.numbers[1])
+      pos = mat * pos
+      command.numbers[0] = pos.x
+      command.numbers[1] = pos.y
+    of HLine, RHLine:
+      var pos = vec2(command.numbers[0], 0)
+      pos = mat * pos
+      command.numbers[0] = pos.x
+    of VLine, RVLine:
+      var pos = vec2(0, command.numbers[0])
+      pos = mat * pos
+      command.numbers[0] = pos.y
+    of Cubic, RCubic:
+      var
+        ctrl1 = vec2(command.numbers[0], command.numbers[1])
+        ctrl2 = vec2(command.numbers[2], command.numbers[3])
+        to = vec2(command.numbers[4], command.numbers[5])
+      ctrl1 = mat * ctrl1
+      ctrl2 = mat * ctrl2
+      to = mat * to
+      command.numbers[0] = ctrl1.x
+      command.numbers[1] = ctrl1.y
+      command.numbers[2] = ctrl2.x
+      command.numbers[3] = ctrl2.y
+      command.numbers[4] = to.x
+      command.numbers[5] = to.y
+    of SCubic, RSCubic, Quad, RQuad:
+      var
+        ctrl = vec2(command.numbers[0], command.numbers[1])
+        to = vec2(command.numbers[2], command.numbers[3])
+      ctrl = mat * ctrl
+      to = mat * to
+      command.numbers[0] = ctrl.x
+      command.numbers[1] = ctrl.y
+      command.numbers[2] = to.x
+      command.numbers[3] = to.y
+    of Arc, RArc:
+      var
+        radii = vec2(command.numbers[0], command.numbers[1])
+        to = vec2(command.numbers[5], command.numbers[6])
+      # Extract the scale from the matrix and only apply that to the radii
+      radii = scale(vec2(mat[0, 0], mat[1, 1])) * radii
+      to = mat * to
+      command.numbers[0] = radii.x
+      command.numbers[1] = radii.y
+      command.numbers[5] = to.x
+      command.numbers[6] = to.y
+
 proc commandsToPolygons*(commands: seq[PathCommand]): seq[seq[Vec2]] =
   ## Converts SVG-like commands to simpler polygon
 
@@ -855,9 +909,19 @@ proc bezierCurveTo*(path: Path, x1, y1, x2, y2, x3, y3: float32) =
     x1, y1, x2, y2, x3, y3
   ]))
 
-proc quadraticCurveTo*(path: Path) =
-  ## Adds a quadratic Bézier curve to the current path.
-  raise newException(ValueError, "not implemented")
+proc quadraticCurveTo*(path: var Path, x1, y1, x2, y2: float32) =
+  ## Adds a quadratic Bézier curve to the path. This requires 2 points.
+  ## The first point is the control point and the second is the end point.
+  ## The starting point is the last point in the current path, which can be
+  ## changed using moveTo() before creating the curve.
+  path.commands.add(PathCommand(
+    kind: Quad,
+    numbers: @[x1, y1, x2, y2]
+  ))
+  path.at = vec2(x2, y2)
+
+proc quadraticCurveTo*(path: var Path, ctrl, to: Vec2) {.inline.} =
+  path.quadraticCurveTo(ctrl.x, ctrl.y, to.x, to.y)
 
 proc arc*(path: Path) =
   ## Adds an arc to the path which is centered at (x, y) position with radius r starting at startAngle and ending at endAngle going in the given direction by anticlockwise (defaulting to clockwise).