From 329fff82f6819beab7ea834b8ecb715bc98f4341 Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Fri, 13 May 2016 18:10:43 -0400
Subject: [PATCH] Some more fixups and cleanups, especially in the matrix code.

---
 common/matrix.c     | 79 +++++++--------------------------------------
 common/uipriv.h     |  6 ----
 darwin/autolayout.m |  1 -
 3 files changed, 12 insertions(+), 74 deletions(-)

diff --git a/common/matrix.c b/common/matrix.c
index ce802d3c..676885d1 100644
--- a/common/matrix.c
+++ b/common/matrix.c
@@ -13,34 +13,22 @@ void uiDrawMatrixSetIdentity(uiDrawMatrix *m)
 	m->M32 = 0;
 }
 
-// TODO don't default to fallback functions within the fallback functions
+// The rest of this file provides basic utilities in case the platform doesn't provide any of its own for these tasks.
+// Keep these as minimal as possible. They should generally not call other fallbacks.
 
 // see https://msdn.microsoft.com/en-us/library/windows/desktop/ff684171%28v=vs.85%29.aspx#skew_transform
-// TODO if Windows 7 is ever dropped change this so we can pass in D2D1Tan()
+// TODO see if there's a way we can avoid the multiplication
 void fallbackSkew(uiDrawMatrix *m, double x, double y, double xamount, double yamount)
 {
 	uiDrawMatrix n;
 
-	setIdentity(&n);
+	uiDrawMatrixSetIdentity(&n);
 	// TODO explain this
 	n.M12 = tan(yamount);
 	n.M21 = tan(xamount);
 	n.M31 = -y * tan(xamount);
 	n.M32 = -x * tan(yamount);
-	fallbackMultiply(m, &n);
-}
-
-// see windows/draw.c for more information
-// TODO we don't need to do this if we can bypass the multiplication somehow
-
-void fallbackTranslate(uiDrawMatrix *m, double x, double y)
-{
-	uiDrawMatrix m2;
-
-	setIdentity(&m2);
-	m2.M31 = x;
-	m2.M32 = y;
-	fallbackMultiply(m, &m2);
+	uiDrawMatrixMultiply(m, &n);
 }
 
 void scaleCenter(double xCenter, double yCenter, double *x, double *y)
@@ -49,57 +37,14 @@ void scaleCenter(double xCenter, double yCenter, double *x, double *y)
 	*y = yCenter - (*y * yCenter);
 }
 
-void fallbackScale(uiDrawMatrix *m, double xCenter, double yCenter, double x, double y)
+// the basic algorithm is from cairo
+// but it's the same algorithm as the transform point, just without M31 and M32 taken into account, so let's just do that instead
+void fallbackTransformSize(uiDrawMatrix *m, double *x, double *y)
 {
 	uiDrawMatrix m2;
 
-	setIdentity(&m2);
-	m2.M11 = x;
-	m2.M22 = y;
-	scaleCenter(xCenter, yCenter, &x, &y);
-	m2.M31 = x;
-	m2.M32 = y;
-	fallbackMultiply(m, &m2);
-}
-
-void fallbackMultiply(uiDrawMatrix *dest, uiDrawMatrix *src)
-{
-	uiDrawMatrix out;
-
-	out.M11 = (dest->M11 * src->M11) +
-		(dest->M12 * src->M21);
-	out.M12 = (dest->M11 * src->M12) +
-		(dest->M12 * src->M22);
-	out.M21 = (dest->M21 * src->M11) +
-		(dest->M22 * src->M21);
-	out.M22 = (dest->M21 * src->M12) +
-		(dest->M22 * src->M22);
-	out.M31 = (dest->M31 * src->M11) +
-		(dest->M32 * src->M21) +
-		src->M31;
-	out.M32 = (dest->M31 * src->M12) +
-		(dest->M32 * src->M22) +
-		src->M32;
-	*dest = out;
-}
-
-void fallbackTransformPoint(uiDrawMatrix *m, double *x, double *y)
-{
-	double xout, yout;
-
-	xout = (*x * m->M11) + (*y * m->M21) + m->M31;
-	yout = (*x * m->M12) + (*y * m->M22) + m->M32;
-	*x = xout;
-	*y = yout;
-}
-
-// and this algorithm is according to cairo
-void fallbackTransformSize(uiDrawMatrix *m, double *x, double *y)
-{
-	double xout, yout;
-
-	xout = (*x * m->M11) + (*y * m->M21);
-	yout = (*x * m->M12) + (*y * m->M22);
-	*x = xout;
-	*y = yout;
+	m2 = *m;
+	m2.M31 = 0;
+	m2.M32 = 0;
+	uiDrawMatrixTransformPoint(&m2, x, y);
 }
diff --git a/common/uipriv.h b/common/uipriv.h
index 673f7a36..37496384 100644
--- a/common/uipriv.h
+++ b/common/uipriv.h
@@ -3,8 +3,6 @@
 extern "C" {
 #endif
 
-// TODO stdlib.h needed?
-#include <stdlib.h>
 #include "controlsigs.h"
 
 extern uiInitOptions options;
@@ -41,11 +39,7 @@ extern int fromScancode(uintptr_t, uiAreaKeyEvent *);
 
 // matrix.c
 extern void fallbackSkew(uiDrawMatrix *, double, double, double, double);
-extern void fallbackTranslate(uiDrawMatrix *, double, double);
 extern void scaleCenter(double, double, double *, double *);
-extern void fallbackScale(uiDrawMatrix *, double, double, double, double);
-extern void fallbackMultiply(uiDrawMatrix *, uiDrawMatrix *);
-extern void fallbackTransformPoint(uiDrawMatrix *, double *, double *);
 extern void fallbackTransformSize(uiDrawMatrix *, double *, double *);
 
 #ifdef __cplusplus
diff --git a/darwin/autolayout.m b/darwin/autolayout.m
index 1b1203b7..19bb26ad 100644
--- a/darwin/autolayout.m
+++ b/darwin/autolayout.m
@@ -37,7 +37,6 @@ static CGFloat margins(int margined)
 void singleChildConstraintsEstablish(struct singleChildConstraints *c, NSView *contentView, NSView *childView, BOOL hugsTrailing, BOOL hugsBottom, int margined, NSString *desc)
 {
 	CGFloat margin;
-	NSLayoutRelation relation;
 
 	margin = margins(margined);