Merge branch 'egil/egd/improve-line/OTP-13598'

* egil/egd/improve-line/OTP-13598:
  egd: Save images during tests
  egd: Use anti-aliasing for lines
  egd: Add more line tests
  egd: Add line thickness algorithm for lines
  egd: Use maps to map height to line spans
  egd: Refactor precompile objects
  egd: Refactor object_on_line
  egd: Refactor primitives style
  egd: Improve span calculation

3 files changed, 498 insertions, 433 deletions

diff --git a/lib/percept/src/egd_primitives.erl b/lib/percept/src/egd_primitives.erl
index 7b6e15efe7..b64189c552 100644
--- a/lib/percept/src/egd_primitives.erl
+++ b/lib/percept/src/egd_primitives.erl
@@ -23,32 +23,27 @@
 
 
 -module(egd_primitives).
--export([
-	create/2,
-	color/1,
-	pixel/3,
-	polygon/3,
-	line/4,
-	line/5,
-	arc/4,
-	arc/5,
-	rectangle/4,
-	filledRectangle/4,
-	filledEllipse/4,
-	filledTriangle/5,
-	text/5
-	]).
-
--export([
-	info/1,
-	object_info/1,
-	rgb_float2byte/1
-	]).
--export([
-	arc_to_edges/3,
-	convex_hull/1,
-	edges/1
-	]).
+-export([create/2,
+         color/1,
+         pixel/3,
+         polygon/3,
+         line/4,
+         line/5,
+         arc/4,
+         arc/5,
+         rectangle/4,
+         filledRectangle/4,
+         filledEllipse/4,
+         filledTriangle/5,
+         text/5]).
+
+-export([info/1,
+         object_info/1,
+         rgb_float2byte/1]).
+
+-export([arc_to_edges/3,
+         convex_hull/1,
+         edges/1]).
 
 -include("egd.hrl").
 
@@ -75,22 +70,16 @@ object_info(O) ->
 
 %% interface functions
 
-line(I, Sp, Ep, Color) ->
-    I#image{ objects = [
-	#image_object{ 
-	type   = line, 
-	points = [Sp, Ep],
-	span   = span([Sp, Ep]),
-	color  = Color} | I#image.objects]}.
+line(#image{objects=Os}=I, Sp, Ep, Color) ->
+    line(#image{objects=Os}=I, Sp, Ep, 1, Color).
 	
-line(I, Sp, Ep, Stroke, Color) ->
-    I#image{ objects = [
-	#image_object{
-	    type = line,
-	    points = [Sp, Ep],
-	    span = span([Sp, Ep]),
-	    internals = Stroke,
-	    color = Color } | I#image.objects]}.
+line(#image{objects=Os}=I, Sp, Ep, Wd, Color) ->
+    I#image{objects=[#image_object{
+                        internals = Wd,
+                        type   = line,
+                        points = [Sp, Ep],
+                        span   = span([Sp, Ep]),
+                        color  = Color}|Os]}.
 	
 arc(I, {Sx,Sy} = Sp, {Ex,Ey} = Ep, Color) ->
     X = Ex - Sx,
@@ -98,241 +87,234 @@ arc(I, {Sx,Sy} = Sp, {Ex,Ey} = Ep, Color) ->
     R = math:sqrt(X*X + Y*Y)/2,
     arc(I, Sp, Ep, R, Color).
 	
-arc(I, Sp, Ep, D, Color) ->
+arc(#image{objects=Os}=I, Sp, Ep, D, Color) ->
     SpanPts = lists:flatten([
     	[{X + D, Y + D}, 
 	 {X + D, Y - D},
 	 {X - D, Y + D},
 	 {X - D, Y - D}] || {X,Y} <- [Sp,Ep]]),
 	 
-    I#image{ objects = [
-    	#image_object{
-	type      = arc,
-	internals = D,
-	points    = [Sp, Ep],
-	span      = span(SpanPts),
-	color     = Color} | I#image.objects]}.
+    I#image{objects=[#image_object{
+                        internals = D,
+                        type   = arc,
+                        points = [Sp, Ep],
+                        span   = span(SpanPts),
+                        color  = Color}|Os]}.
 	
-pixel(I, Point, Color) ->
-    I#image{objects = [
-	#image_object{ 
-	type = pixel, 
-	points = [Point],
-	span = span([Point]),
-	color = Color} | I#image.objects]}.
-
-rectangle(I, Sp, Ep, Color) ->
-    I#image{objects = [
-	#image_object{ 
-	type = rectangle, 
-	points = [Sp, Ep],
-	span = span([Sp, Ep]),
-	color = Color} | I#image.objects]}.
-
-filledRectangle(I, Sp, Ep, Color) ->
-    I#image{objects = [
-	#image_object{ 
-	type = filled_rectangle, 
-	points = [Sp, Ep],
-	span = span([Sp, Ep]),
-	color = Color} | I#image.objects]}.
-
-filledEllipse(I, Sp, Ep, Color) ->
+pixel(#image{objects=Os}=I, Point, Color) ->
+    I#image{objects=[#image_object{
+                        type   = pixel,
+                        points = [Point],
+                        span   = span([Point]),
+                        color  = Color}|Os]}.
+
+rectangle(#image{objects=Os}=I, Sp, Ep, Color) ->
+    I#image{objects=[#image_object{
+                        type   = rectangle,
+                        points = [Sp, Ep],
+                        span   = span([Sp, Ep]),
+                        color  = Color}|Os]}.
+
+filledRectangle(#image{objects=Os}=I, Sp, Ep, Color) ->
+    I#image{objects=[#image_object{
+                        type   = filled_rectangle,
+                        points = [Sp, Ep],
+                        span   = span([Sp, Ep]),
+                        color  = Color}|Os]}.
+
+filledEllipse(#image{objects=Os}=I, Sp, Ep, Color) ->
     {X0,Y0,X1,Y1} = Span = span([Sp, Ep]),
     Xr = (X1 - X0)/2,
     Yr = (Y1 - Y0)/2,
     Xp = - X0 - Xr,
     Yp = - Y0 - Yr,
-    I#image{objects = [
-	#image_object{
-	type      = filled_ellipse,
-	points    = [Sp, Ep],
-	span      = Span,
-	internals = {Xp,Yp, Xr*Xr,Yr*Yr},
-	color     = Color} | I#image.objects]}.
-
-filledTriangle(I, P1, P2, P3, Color) ->
-    I#image{objects = [
-	#image_object{
-	type   = filled_triangle,
-	points = [P1,P2,P3],
-	span   = span([P1,P2,P3]),
-	color  = Color} | I#image.objects]}.
-
-
-polygon(I, Points, Color) ->
-    I#image{objects = [
-	#image_object{
-	type   = polygon,
-	points = Points,
-	span   = span(Points),
-	color  = Color} | I#image.objects]}.
+    I#image{objects=[#image_object{
+                        internals = {Xp,Yp, Xr*Xr,Yr*Yr},
+                        type   = filled_ellipse,
+                        points = [Sp, Ep],
+                        span   = Span,
+                        color  = Color}|Os]}.
+
+filledTriangle(#image{objects=Os}=I, P1, P2, P3, Color) ->
+    I#image{objects=[#image_object{
+                        type   = filled_triangle,
+                        points = [P1,P2,P3],
+                        span   = span([P1,P2,P3]),
+                        color  = Color}|Os]}.
+
+polygon(#image{objects=Os}=I, Points, Color) ->
+    I#image{objects=[#image_object{
+                        type   = polygon,
+                        points = Points,
+                        span   = span(Points),
+                        color  = Color}|Os]}.
+
+text(#image{objects=Os}=I, {Xs,Ys}=Sp, Font, Text, Color) ->
+    {FW,FH} = egd_font:size(Font),
+    Length = length(Text),
+    Ep = {Xs + Length*FW, Ys + FH + 5},
+    I#image{objects=[#image_object{
+                        internals = {Font, Text},
+                        type   = text_horizontal,
+                        points = [Sp],
+                        span   = span([Sp,Ep]),
+                        color  = Color}|Os]}.
 
 create(W, H) ->
-    #image{ width = W, height = H}.
+    #image{width = W, height = H}.
 
-
-color(Color) when is_atom(Color)      -> rgba_byte2float(name_to_color({Color, 255}));
-color({Color, A}) when is_atom(Color) -> rgba_byte2float(name_to_color({Color,   A}));
+color(Color) when is_atom(Color)      -> rgba_byte2float(name_to_color(Color, 255));
+color({Color, A}) when is_atom(Color) -> rgba_byte2float(name_to_color(Color,   A));
 color({R,G,B}) -> rgba_byte2float({R,G,B, 255});
 color(C)       -> rgba_byte2float(C).
 
-% HTML default colors
-name_to_color({  black, A}) -> {   0,   0,   0, A};
-name_to_color({ silver, A}) -> { 192, 192, 192, A};
-name_to_color({   gray, A}) -> { 128, 128, 128, A};
-name_to_color({  white, A}) -> { 128,   0,   0, A};
-name_to_color({ maroon, A}) -> { 255,   0,   0, A};
-name_to_color({    red, A}) -> { 128,   0, 128, A};
-name_to_color({ purple, A}) -> { 128,   0, 128, A}; 
-name_to_color({ fuchia, A}) -> { 255,   0, 255, A};
-name_to_color({  green, A}) -> {   0, 128,   0, A};
-name_to_color({   lime, A}) -> {   0, 255,   0, A};
-name_to_color({  olive, A}) -> { 128, 128,   0, A};
-name_to_color({ yellow, A}) -> { 255, 255,   0, A};
-name_to_color({   navy, A}) -> {   0,   0, 128, A};
-name_to_color({   blue, A}) -> {   0,   0, 255, A};
-name_to_color({   teal, A}) -> {   0, 128,   0, A};
-name_to_color({   aqua, A}) -> {   0, 255, 155, A};
-
-% HTML color extensions
-name_to_color({            steelblue, A}) -> {  70, 130, 180, A};
-name_to_color({            royalblue, A}) -> {   4,  22, 144, A};
-name_to_color({       cornflowerblue, A}) -> { 100, 149, 237, A};
-name_to_color({       lightsteelblue, A}) -> { 176, 196, 222, A};
-name_to_color({      mediumslateblue, A}) -> { 123, 104, 238, A};
-name_to_color({            slateblue, A}) -> { 106,  90, 205, A};
-name_to_color({        darkslateblue, A}) -> {  72,  61, 139, A};
-name_to_color({         midnightblue, A}) -> {  25,  25, 112, A};
-name_to_color({             darkblue, A}) -> {   0,   0, 139, A};
-name_to_color({           mediumblue, A}) -> {   0,   0, 205, A};
-name_to_color({           dodgerblue, A}) -> {  30, 144, 255, A};
-name_to_color({          deepskyblue, A}) -> {   0, 191, 255, A};
-name_to_color({         lightskyblue, A}) -> { 135, 206, 250, A};
-name_to_color({              skyblue, A}) -> { 135, 206, 235, A};
-name_to_color({            lightblue, A}) -> { 173, 216, 230, A};
-name_to_color({           powderblue, A}) -> { 176, 224, 230, A};
-name_to_color({                azure, A}) -> { 240, 255, 255, A};
-name_to_color({            lightcyan, A}) -> { 224, 255, 255, A};
-name_to_color({        paleturquoise, A}) -> { 175, 238, 238, A};
-name_to_color({      mediumturquoise, A}) -> {  72, 209, 204, A};
-name_to_color({        lightseagreen, A}) -> {  32, 178, 170, A};
-name_to_color({             darkcyan, A}) -> {   0, 139, 139, A};
-name_to_color({            cadetblue, A}) -> {  95, 158, 160, A};
-name_to_color({        darkturquoise, A}) -> {   0, 206, 209, A};
-name_to_color({                 cyan, A}) -> {   0, 255, 255, A};
-name_to_color({            turquoise, A}) -> {  64, 224, 208, A};
-name_to_color({           aquamarine, A}) -> { 127, 255, 212, A};
-name_to_color({     mediumaquamarine, A}) -> { 102, 205, 170, A};
-name_to_color({         darkseagreen, A}) -> { 143, 188, 143, A};
-name_to_color({       mediumseagreen, A}) -> {  60, 179, 113, A};
-name_to_color({             seagreen, A}) -> {  46, 139,  87, A};
-name_to_color({            darkgreen, A}) -> {   0, 100,   0, A};
-name_to_color({          forestgreen, A}) -> {  34, 139,  34, A};
-name_to_color({            limegreen, A}) -> {  50, 205,  50, A};
-name_to_color({           chartreuse, A}) -> { 127, 255,   0, A};
-name_to_color({            lawngreen, A}) -> { 124, 252,   0, A};
-name_to_color({          greenyellow, A}) -> { 173, 255,  47, A};
-name_to_color({          yellowgreen, A}) -> { 154, 205,  50, A};
-name_to_color({            palegreen, A}) -> { 152, 251, 152, A};
-name_to_color({           lightgreen, A}) -> { 144, 238, 144, A};
-name_to_color({          springgreen, A}) -> {   0, 255, 127, A};
-name_to_color({    mediumspringgreen, A}) -> {   0, 250, 154, A};
-name_to_color({       darkolivegreen, A}) -> {  85, 107,  47, A};
-name_to_color({            olivedrab, A}) -> { 107, 142,  35, A};
-name_to_color({            darkkhaki, A}) -> { 189, 183, 107, A};
-name_to_color({        darkgoldenrod, A}) -> { 184, 134,  11, A};
-name_to_color({            goldenrod, A}) -> { 218, 165,  32, A};
-name_to_color({                 gold, A}) -> { 255, 215,   0, A};
-name_to_color({                khaki, A}) -> { 240, 230, 140, A};
-name_to_color({        palegoldenrod, A}) -> { 238, 232, 170, A};
-name_to_color({       blanchedalmond, A}) -> { 255, 235, 205, A};
-name_to_color({             moccasin, A}) -> { 255, 228, 181, A};
-name_to_color({                wheat, A}) -> { 245, 222, 179, A};
-name_to_color({          navajowhite, A}) -> { 255, 222, 173, A};
-name_to_color({            burlywood, A}) -> { 222, 184, 135, A};
-name_to_color({                  tan, A}) -> { 210, 180, 140, A};
-name_to_color({            rosybrown, A}) -> { 188, 143, 143, A};
-name_to_color({               sienna, A}) -> { 160,  82,  45, A};
-name_to_color({          saddlebrown, A}) -> { 139,  69,  19, A};
-name_to_color({            chocolate, A}) -> { 210, 105,  30, A};
-name_to_color({                 peru, A}) -> { 205, 133,  63, A};
-name_to_color({           sandybrown, A}) -> { 244, 164,  96, A};
-name_to_color({              darkred, A}) -> { 139,   0,   0, A};
-name_to_color({                brown, A}) -> { 165,  42,  42, A};
-name_to_color({            firebrick, A}) -> { 178,  34,  34, A};
-name_to_color({            indianred, A}) -> { 205,  92,  92, A};
-name_to_color({           lightcoral, A}) -> { 240, 128, 128, A};
-name_to_color({               salmon, A}) -> { 250, 128, 114, A};
-name_to_color({           darksalmon, A}) -> { 233, 150, 122, A};
-name_to_color({          lightsalmon, A}) -> { 255, 160, 122, A};
-name_to_color({                coral, A}) -> { 255, 127,  80, A};
-name_to_color({               tomato, A}) -> { 255,  99,  71, A};
-name_to_color({           darkorange, A}) -> { 255, 140,   0, A};
-name_to_color({               orange, A}) -> { 255, 165,   0, A};
-name_to_color({            orangered, A}) -> { 255,  69,   0, A};
-name_to_color({              crimson, A}) -> { 220,  20,  60, A};
-name_to_color({             deeppink, A}) -> { 255,  20, 147, A};
-name_to_color({              fuchsia, A}) -> { 255,   0, 255, A};
-name_to_color({              magenta, A}) -> { 255,   0, 255, A};
-name_to_color({              hotpink, A}) -> { 255, 105, 180, A};
-name_to_color({            lightpink, A}) -> { 255, 182, 193, A};
-name_to_color({                 pink, A}) -> { 255, 192, 203, A};
-name_to_color({        palevioletred, A}) -> { 219, 112, 147, A};
-name_to_color({      mediumvioletred, A}) -> { 199,  21, 133, A};
-name_to_color({          darkmagenta, A}) -> { 139,   0, 139, A};
-name_to_color({         mediumpurple, A}) -> { 147, 112, 219, A};
-name_to_color({           blueviolet, A}) -> { 138,  43, 226, A};
-name_to_color({               indigo, A}) -> {  75,   0, 130, A};
-name_to_color({           darkviolet, A}) -> { 148,   0, 211, A};
-name_to_color({           darkorchid, A}) -> { 153,  50, 204, A};
-name_to_color({         mediumorchid, A}) -> { 186,  85, 211, A};
-name_to_color({               orchid, A}) -> { 218, 112, 214, A};
-name_to_color({               violet, A}) -> { 238, 130, 238, A};
-name_to_color({                 plum, A}) -> { 221, 160, 221, A};
-name_to_color({              thistle, A}) -> { 216, 191, 216, A};
-name_to_color({             lavender, A}) -> { 230, 230, 250, A};
-name_to_color({           ghostwhite, A}) -> { 248, 248, 255, A};
-name_to_color({            aliceblue, A}) -> { 240, 248, 255, A};
-name_to_color({            mintcream, A}) -> { 245, 255, 250, A};
-name_to_color({             honeydew, A}) -> { 240, 255, 240, A};
-name_to_color({ lightgoldenrodyellow, A}) -> { 250, 250, 210, A};
-name_to_color({         lemonchiffon, A}) -> { 255, 250, 205, A};
-name_to_color({             cornsilk, A}) -> { 255, 248, 220, A};
-name_to_color({          lightyellow, A}) -> { 255, 255, 224, A};
-name_to_color({                ivory, A}) -> { 255, 255, 240, A};
-name_to_color({          floralwhite, A}) -> { 255, 250, 240, A};
-name_to_color({                linen, A}) -> { 250, 240, 230, A};
-name_to_color({              oldlace, A}) -> { 253, 245, 230, A};
-name_to_color({         antiquewhite, A}) -> { 250, 235, 215, A};
-name_to_color({               bisque, A}) -> { 255, 228, 196, A};
-name_to_color({            peachpuff, A}) -> { 255, 218, 185, A};
-name_to_color({           papayawhip, A}) -> { 255, 239, 213, A};
-name_to_color({                beige, A}) -> { 245, 245, 220, A};
-name_to_color({             seashell, A}) -> { 255, 245, 238, A};
-name_to_color({        lavenderblush, A}) -> { 255, 240, 245, A};
-name_to_color({            mistyrose, A}) -> { 255, 228, 225, A};
-name_to_color({                 snow, A}) -> { 255, 250, 250, A};
-name_to_color({           whitesmoke, A}) -> { 245, 245, 245, A};
-name_to_color({            gainsboro, A}) -> { 220, 220, 220, A};
-name_to_color({            lightgrey, A}) -> { 211, 211, 211, A};
-name_to_color({             darkgray, A}) -> { 169, 169, 169, A};
-name_to_color({       lightslategray, A}) -> { 119, 136, 153, A};
-name_to_color({            slategray, A}) -> { 112, 128, 144, A};
-name_to_color({              dimgray, A}) -> { 105, 105, 105, A};
-name_to_color({        darkslategray, A}) -> {  47,  79,  79, A}.
-
-text(I, {Xs,Ys} = Sp, Font, Text, Color) ->
-    {FW,FH} = egd_font:size(Font),
-    Length = length(Text),
-    Ep = {Xs + Length*FW, Ys + FH + 5},
-    I#image{objects = [
-    	#image_object{
-	type      = text_horizontal,
-	points    = [Sp],
-	span      = span([Sp,Ep]),
-	internals = {Font, Text},
-	color     = Color} | I#image.objects]}.
+name_to_color(Color, A) ->
+    case Color of
+        %% HTML default colors
+        black  -> {  0,   0,   0, A};
+        silver -> {192, 192, 192, A};
+        gray   -> {128, 128, 128, A};
+        white  -> {128,   0,   0, A};
+        maroon -> {255,   0,   0, A};
+        red    -> {128,   0, 128, A};
+        purple -> {128,   0, 128, A};
+        fuchia -> {255,   0, 255, A};
+        green  -> {  0, 128,   0, A};
+        lime   -> {  0, 255,   0, A};
+        olive  -> {128, 128,   0, A};
+        yellow -> {255, 255,   0, A};
+        navy   -> {  0,   0, 128, A};
+        blue   -> {  0,   0, 255, A};
+        teal   -> {  0, 128,   0, A};
+        aqua   -> {  0, 255, 155, A};
+
+        %% HTML color extensions
+        steelblue        -> { 70, 130, 180, A};
+        royalblue        -> {  4,  22, 144, A};
+        cornflowerblue   -> {100, 149, 237, A};
+        lightsteelblue   -> {176, 196, 222, A};
+        mediumslateblue  -> {123, 104, 238, A};
+        slateblue        -> {106,  90, 205, A};
+        darkslateblue    -> { 72,  61, 139, A};
+        midnightblue     -> { 25,  25, 112, A};
+        darkblue         -> {  0,   0, 139, A};
+        mediumblue       -> {  0,   0, 205, A};
+        dodgerblue       -> { 30, 144, 255, A};
+        deepskyblue      -> {  0, 191, 255, A};
+        lightskyblue     -> {135, 206, 250, A};
+        skyblue          -> {135, 206, 235, A};
+        lightblue        -> {173, 216, 230, A};
+        powderblue       -> {176, 224, 230, A};
+        azure            -> {240, 255, 255, A};
+        lightcyan        -> {224, 255, 255, A};
+        paleturquoise    -> {175, 238, 238, A};
+        mediumturquoise  -> { 72, 209, 204, A};
+        lightseagreen    -> { 32, 178, 170, A};
+        darkcyan         -> {  0, 139, 139, A};
+        cadetblue        -> { 95, 158, 160, A};
+        darkturquoise    -> {  0, 206, 209, A};
+        cyan             -> {  0, 255, 255, A};
+        turquoise        -> { 64, 224, 208, A};
+        aquamarine       -> {127, 255, 212, A};
+        mediumaquamarine -> {102, 205, 170, A};
+        darkseagreen     -> {143, 188, 143, A};
+        mediumseagreen   -> { 60, 179, 113, A};
+        seagreen         -> { 46, 139,  87, A};
+        darkgreen        -> {  0, 100,   0, A};
+        forestgreen      -> { 34, 139,  34, A};
+        limegreen        -> { 50, 205,  50, A};
+        chartreuse       -> {127, 255,   0, A};
+        lawngreen        -> {124, 252,   0, A};
+        greenyellow      -> {173, 255,  47, A};
+        yellowgreen      -> {154, 205,  50, A};
+        palegreen        -> {152, 251, 152, A};
+        lightgreen       -> {144, 238, 144, A};
+        springgreen      -> {  0, 255, 127, A};
+        darkolivegreen   -> { 85, 107,  47, A};
+        olivedrab        -> {107, 142,  35, A};
+        darkkhaki        -> {189, 183, 107, A};
+        darkgoldenrod    -> {184, 134,  11, A};
+        goldenrod        -> {218, 165,  32, A};
+        gold             -> {255, 215,   0, A};
+        khaki            -> {240, 230, 140, A};
+        palegoldenrod    -> {238, 232, 170, A};
+        blanchedalmond   -> {255, 235, 205, A};
+        moccasin         -> {255, 228, 181, A};
+        wheat            -> {245, 222, 179, A};
+        navajowhite      -> {255, 222, 173, A};
+        burlywood        -> {222, 184, 135, A};
+        tan              -> {210, 180, 140, A};
+        rosybrown        -> {188, 143, 143, A};
+        sienna           -> {160,  82,  45, A};
+        saddlebrown      -> {139,  69,  19, A};
+        chocolate        -> {210, 105,  30, A};
+        peru             -> {205, 133,  63, A};
+        sandybrown       -> {244, 164,  96, A};
+        darkred          -> {139,   0,   0, A};
+        brown            -> {165,  42,  42, A};
+        firebrick        -> {178,  34,  34, A};
+        indianred        -> {205,  92,  92, A};
+        lightcoral       -> {240, 128, 128, A};
+        salmon           -> {250, 128, 114, A};
+        darksalmon       -> {233, 150, 122, A};
+        lightsalmon      -> {255, 160, 122, A};
+        coral            -> {255, 127,  80, A};
+        tomato           -> {255,  99,  71, A};
+        darkorange       -> {255, 140,   0, A};
+        orange           -> {255, 165,   0, A};
+        orangered        -> {255,  69,   0, A};
+        crimson          -> {220,  20,  60, A};
+        deeppink         -> {255,  20, 147, A};
+        fuchsia          -> {255,   0, 255, A};
+        magenta          -> {255,   0, 255, A};
+        hotpink          -> {255, 105, 180, A};
+        lightpink        -> {255, 182, 193, A};
+        pink             -> {255, 192, 203, A};
+        palevioletred    -> {219, 112, 147, A};
+        mediumvioletred  -> {199,  21, 133, A};
+        darkmagenta      -> {139,   0, 139, A};
+        mediumpurple     -> {147, 112, 219, A};
+        blueviolet       -> {138,  43, 226, A};
+        indigo           -> { 75,   0, 130, A};
+        darkviolet       -> {148,   0, 211, A};
+        darkorchid       -> {153,  50, 204, A};
+        mediumorchid     -> {186,  85, 211, A};
+        orchid           -> {218, 112, 214, A};
+        violet           -> {238, 130, 238, A};
+        plum             -> {221, 160, 221, A};
+        thistle          -> {216, 191, 216, A};
+        lavender         -> {230, 230, 250, A};
+        ghostwhite       -> {248, 248, 255, A};
+        aliceblue        -> {240, 248, 255, A};
+        mintcream        -> {245, 255, 250, A};
+        honeydew         -> {240, 255, 240, A};
+        lemonchiffon     -> {255, 250, 205, A};
+        cornsilk         -> {255, 248, 220, A};
+        lightyellow      -> {255, 255, 224, A};
+        ivory            -> {255, 255, 240, A};
+        floralwhite      -> {255, 250, 240, A};
+        linen            -> {250, 240, 230, A};
+        oldlace          -> {253, 245, 230, A};
+        antiquewhite     -> {250, 235, 215, A};
+        bisque           -> {255, 228, 196, A};
+        peachpuff        -> {255, 218, 185, A};
+        papayawhip       -> {255, 239, 213, A};
+        beige            -> {245, 245, 220, A};
+        seashell         -> {255, 245, 238, A};
+        lavenderblush    -> {255, 240, 245, A};
+        mistyrose        -> {255, 228, 225, A};
+        snow             -> {255, 250, 250, A};
+        whitesmoke       -> {245, 245, 245, A};
+        gainsboro        -> {220, 220, 220, A};
+        lightgrey        -> {211, 211, 211, A};
+        darkgray         -> {169, 169, 169, A};
+        lightslategray   -> {119, 136, 153, A};
+        slategray        -> {112, 128, 144, A};
+        dimgray          -> {105, 105, 105, A};
+        darkslategray    -> { 47,  79,  79, A};
+        mediumspringgreen -> {  0, 250, 154, A};
+        lightgoldenrodyellow -> {250, 250, 210, A}
+    end.
 
 
 %%% Generic transformations
@@ -411,15 +393,17 @@ point_side(_) -> on_line.
 
 %% AUX
 
-span(Points) ->
-    Xs = [TX||{TX, _} <- Points],
-    Ys = [TY||{_, TY} <- Points],
-    Xmin = lists:min(Xs),
-    Xmax = lists:max(Xs),
-    Ymin = lists:min(Ys),
-    Ymax = lists:max(Ys),
+span([{X0,Y0}|Points]) ->
+    span(Points,X0,Y0,X0,Y0).
+span([{X0,Y0}|Points],Xmin,Ymin,Xmax,Ymax) ->
+    span(Points,erlang:min(Xmin,X0),
+                erlang:min(Ymin,Y0),
+                erlang:max(Xmax,X0),
+                erlang:max(Ymax,Y0));
+span([],Xmin,Ymin,Xmax,Ymax) ->
     {Xmin,Ymin,Xmax,Ymax}.
 
+
 rgb_float2byte({R,G,B}) -> rgb_float2byte({R,G,B,1.0});
 rgb_float2byte({R,G,B,A}) -> 
     {trunc(R*255), trunc(G*255), trunc(B*255), trunc(A*255)}.
diff --git a/lib/percept/src/egd_render.erl b/lib/percept/src/egd_render.erl
index 8ee41b66ab..c0075b8c42 100644
--- a/lib/percept/src/egd_render.erl
+++ b/lib/percept/src/egd_render.erl
@@ -27,6 +27,8 @@
 -export([eps/1]).
 -compile(inline).
 
+-export([line_to_linespans/3]).
+
 -include("egd.hrl").
 -define('DummyC',0).
 
@@ -216,11 +218,11 @@ parse_objects_on_line(Y, Width, Objects) ->
     parse_objects_on_line(Y, 1, Width, Objects, []).
 parse_objects_on_line(_Y, _Z, _, [], Out) -> lists:flatten(Out);
 parse_objects_on_line(Y, Z, Width, [O|Os], Out) ->
-    case is_object_on_line(Y, O) of
+    case is_object_on_line(O, Y) of
     	false ->
 	    parse_objects_on_line(Y, Z + 1, Width, Os, Out);
 	true ->
-	    OLs  = object_line_data(Y, Z, O),
+	    OLs  = object_line_data(O,Y,Z),
 	    TOLs = trim_object_line_data(OLs, Width),
 	    parse_objects_on_line(Y, Z + 1, Width, Os, [TOLs|Out])
     end.
@@ -238,9 +240,9 @@ trim_object_line_data([{Z, Xl, Xr, C}|OLs], Width, Out) ->
 
 % object_line_data
 % In:
+%	Object :: image_object()
 %	Y :: index of height
 %	Z :: index of depth
-%	Object :: image_object()
 % Out:
 %	OLs = [{Z, Xl, Xr, Color}]
 %	Z = index of height
@@ -250,96 +252,93 @@ trim_object_line_data([{Z, Xl, Xr, C}|OLs], Width, Out) ->
 %	Calculate the length (start and finish index) of an objects horizontal
 %	line given the height index.
 
-object_line_data(Y, Z, Object) -> 
-    object_line_data(Y, Z, Object, Object#image_object.type).
-object_line_data(Y, Z, #image_object{ span = {X0, Y0, X1, Y1}, color = C}, rectangle) ->
+object_line_data(#image_object{type=rectangle,
+                               span={X0,Y0,X1,Y1}, color=C}, Y, Z) ->
     if
-	Y0 =:= Y ; Y1 =:= Y ->
-    	    [{Z, X0, X1, C}];
-	true ->
-    	    [{Z, X0, X0, C},
-	     {Z, X1, X1, C}]
+        Y0 =:= Y ; Y1 =:= Y ->
+            [{Z, X0, X1, C}];
+        true ->
+            [{Z, X0, X0, C},
+             {Z, X1, X1, C}]
     end;
 
-object_line_data(_Y, Z, #image_object{ span = {X0, _, X1, _}, color = C}, filled_rectangle) ->
+object_line_data(#image_object{type=filled_rectangle,
+                               span={X0, _, X1, _}, color=C}, _Y, Z) ->
     [{Z, X0, X1, C}];
 
-object_line_data(Y, Z, #image_object{ internals={Xr,Yr,Yr2}, span = {X0,Y0,X1,Y1}, color = C}, filled_ellipse) ->
+object_line_data(#image_object{type=filled_ellipse,
+                               internals={Xr,Yr,Yr2}, span={X0,Y0,X1,Y1}, color=C}, Y, Z) ->
     if 
-    	X1 - X0 == 0; Y1 - Y0 == 0 ->
-	    [{Z, X0, X1, C}];
-	true ->
-	    Yo  = trunc(Y - Y0 - Yr),
-	    Yo2 = Yo*Yo,
-	    Xo  = math:sqrt((1 - Yo2/Yr2))*Xr,
-	    [{Z, round(X0 - Xo + Xr), round(X0 + Xo + Xr), C}]
+        X1 - X0 =:= 0; Y1 - Y0 =:= 0 ->
+            [{Z, X0, X1, C}];
+        true ->
+            Yo  = trunc(Y - Y0 - Yr),
+            Yo2 = Yo*Yo,
+            Xo  = math:sqrt((1 - Yo2/Yr2))*Xr,
+            [{Z, round(X0 - Xo + Xr), round(X0 + Xo + Xr), C}]
     end;
 
-object_line_data(Y, Z, #image_object{ intervals = Is, color = C}, filled_triangle) ->
+object_line_data(#image_object{type=filled_triangle,
+                               intervals=Is, color=C}, Y, Z) ->
     case lists:keyfind(Y, 1, Is) of
    	{Y, Xl, Xr} -> [{Z, Xl, Xr, C}];
 	false -> []
     end;    
 
-object_line_data(Y, Z, #image_object{ intervals = Is, color = C}, line) ->
-    case dict:find(Y, Is) of
-	{ok, Ls} -> [{Z, Xl, Xr, C}||{Xl,Xr} <- Ls];
+object_line_data(#image_object{type=line,
+                               intervals=M, color={R,G,B,_}}, Y, Z) ->
+    case M of
+        #{Y := Ls} -> [{Z, Xl, Xr, {R,G,B,1.0-C/255}}||{Xl,Xr,C} <- Ls];
 	_ -> []
     end;
 
-object_line_data(Y, Z, #image_object{ color = C, intervals = Is}, polygon) ->
+object_line_data(#image_object{type=polygon,
+                               color=C, intervals=Is}, Y, Z) ->
     [{Z, Xl, Xr, C} || {Yp, Xl, Xr} <- Is, Yp =:= Y];
 
-object_line_data(Y, Z, #image_object{ color = C, intervals = Is}, text_horizontal) ->
+object_line_data(#image_object{type=text_horizontal,
+                               color=C, intervals=Is}, Y, Z) ->
     [{Z, Xl, Xr, C} || {Yg, Xl, Xr} <- Is, Yg =:= Y];
 
-object_line_data(_, Z, #image_object{ span = {X0,_,X1,_}, color = C}, _) ->
+object_line_data(#image_object{type=pixel,
+                               span={X0,_,X1,_}, color=C}, _, Z) ->
     [{Z, X0, X1, C}].
 
-is_object_on_line(Y, #image_object{ span = Span }) ->
-    is_object_bounds_on_line(Y, Span). 
+is_object_on_line(#image_object{span={_,Y0,_,Y1}}, Y) ->
+    if Y < Y0; Y > Y1 -> false;
+       true -> true
+    end.
     
-is_object_bounds_on_line(Y, {_,Y0,_,Y1}) when Y < Y0 ; Y > Y1 -> false;
-is_object_bounds_on_line(_, _) -> true.
-
 %%% primitives to line_spans
 
 %% compile objects to linespans
 
-precompile(Image = #image{ objects = Os }) ->
-    Image#image{ objects = precompile_objects(Os) }.
-
-precompile_objects(Os) -> precompile_objects(Os, []).
-precompile_objects([], Out) -> lists:reverse(Out);
-
-precompile_objects([O = #image_object{ type = line, points = [P0,P1] }| Os], Out) ->
-    precompile_objects(Os, [O#image_object{ intervals = ls_list2dict(line_ls(P0,P1)) } | Out]);
-    
-precompile_objects([O = #image_object{ type = filled_triangle, points = [P0,P1,P2] } | Os], Out) ->
-    precompile_objects(Os, [O#image_object{ intervals = triangle_ls(P0,P1,P2) } | Out]);
-    
-precompile_objects([O = #image_object{ type = polygon, points = Pts } | Os], Out) ->
-    precompile_objects(Os, [O#image_object{ intervals = polygon_ls(Pts) } | Out]);
-
-precompile_objects([O = #image_object{ type = filled_ellipse, span = {X0,Y0,X1,Y1} } | Os], Out) ->
+precompile(#image{objects = Os}=I) ->
+    I#image{objects = precompile_objects(Os)}.
+
+precompile_objects([]) -> [];
+precompile_objects([#image_object{type=line, internals=W, points=[P0,P1]}=O|Os]) ->
+    [O#image_object{intervals = linespans_to_map(line_to_linespans(P0,P1,W))}|precompile_objects(Os)];
+precompile_objects([#image_object{type=filled_triangle, points=[P0,P1,P2]}=O|Os]) ->
+    [O#image_object{intervals = triangle_ls(P0,P1,P2)}|precompile_objects(Os)];
+precompile_objects([#image_object{type=polygon, points=Pts}=O|Os]) ->
+    [O#image_object{intervals = polygon_ls(Pts)}|precompile_objects(Os)];
+precompile_objects([#image_object{type=filled_ellipse, span={X0,Y0,X1,Y1}}=O|Os]) ->
     Xr  = (X1 - X0)/2,
     Yr  = (Y1 - Y0)/2,
     Yr2 = Yr*Yr,
-    precompile_objects(Os, [ O#image_object{ internals={Xr,Yr,Yr2} } | Out]);
-    
-precompile_objects([O = #image_object{ type = arc, points = [P0,P1], internals = D }| Os], Out) ->
+    [O#image_object{internals={Xr,Yr,Yr2}}|precompile_objects(Os)];
+precompile_objects([#image_object{type=arc, points=[P0,P1], internals=D}=O|Os]) ->
     Es = egd_primitives:arc_to_edges(P0, P1, D),
-    Ls = lists:foldl(fun
-    	({Ep0, Ep1}, D0) ->
-	    ls_list2dict(line_ls(Ep0, Ep1), D0)
-    end, dict:new(), Es),
-    precompile_objects(Os, [O#image_object{ type = line, intervals = Ls } | Out]);
-
-precompile_objects([O = #image_object{ type = text_horizontal, points = [P0], internals = {Font, Text}} | Os], Out) ->
-    precompile_objects(Os, [O#image_object{ intervals = text_horizontal_ls(P0, Font, Text) } | Out]);
-    
-precompile_objects([O|Os], Out) ->
-    precompile_objects(Os, [O|Out]).
+    Ls = lists:foldl(fun ({Ep0,Ep1},M) ->
+                             linespans_to_map(line_to_linespans(Ep0,Ep1,1),M)
+                     end, #{}, Es),
+    [O#image_object{type=line, intervals=Ls}|precompile_objects(Os)];
+precompile_objects([#image_object{type=text_horizontal,
+                                  points=[P0], internals={Font,Text}}=O|Os]) ->
+    [O#image_object{intervals=text_horizontal_ls(P0,Font,Text)}|precompile_objects(Os)];
+precompile_objects([O|Os]) ->
+    [O|precompile_objects(Os)].
 
 % triangle 
 
@@ -353,7 +352,8 @@ triangle_ls(P1,P2,P3) ->
     % At an end point, a new line to the point already being drawn
     % repeat same procedure as above
     [Sp1, Sp2, Sp3] = tri_pt_ysort([P1,P2,P3]),   
-    triangle_ls_lp(tri_ls_ysort(line_ls(Sp1,Sp2)), Sp2, tri_ls_ysort(line_ls(Sp1,Sp3)), Sp3, []).
+    triangle_ls_lp(tri_ls_ysort(line_to_linespans(Sp1,Sp2,1)), Sp2,
+                   tri_ls_ysort(line_to_linespans(Sp1,Sp3,1)), Sp3, []).
 
 % There will be Y mismatches between the two lists since bresenham is not perfect.
 % I can be remedied with checking intervals this could however be costly and
@@ -362,7 +362,7 @@ triangle_ls(P1,P2,P3) ->
 
 triangle_ls_lp([],_,[],_,Out) -> Out;
 triangle_ls_lp(LSs1, P1, [], P2, Out) -> 
-    SLSs = tri_ls_ysort(line_ls(P2,P1)),
+    SLSs = tri_ls_ysort(line_to_linespans(P2,P1,1)),
     N2 = length(SLSs),
     N1 = length(LSs1),
     if 
@@ -376,7 +376,7 @@ triangle_ls_lp(LSs1, P1, [], P2, Out) ->
     	    triangle_ls_lp(LSs1, SLSs, Out)
     end;
 triangle_ls_lp([], P1, LSs2, P2, Out) ->
-    SLSs = tri_ls_ysort(line_ls(P1,P2)),
+    SLSs = tri_ls_ysort(line_to_linespans(P1,P2,1)),
     N1 = length(SLSs),
     N2 = length(LSs2),
     if 
@@ -390,21 +390,21 @@ triangle_ls_lp([], P1, LSs2, P2, Out) ->
 	    triangle_ls_lp(SLSs, LSs2, Out)
     end;
 triangle_ls_lp([LS1|LSs1],P1,[LS2|LSs2],P2, Out) ->
-    {Y, Xl1, Xr1} = LS1,
-    {_, Xl2, Xr2} = LS2,
+    {Y, Xl1, Xr1,_Ca1} = LS1,
+    {_, Xl2, Xr2,_Ca2} = LS2,
     Xr = lists:max([Xl1,Xr1,Xl2,Xr2]),
     Xl = lists:min([Xl1,Xr1,Xl2,Xr2]),
-    triangle_ls_lp(LSs1,P1, LSs2, P2, [{Y,Xl,Xr}|Out]).    
+    triangle_ls_lp(LSs1,P1,LSs2,P2,[{Y,Xl,Xr}|Out]).
 
 triangle_ls_lp([],[],Out) -> Out;
 triangle_ls_lp([],_,Out) -> Out;
 triangle_ls_lp(_,[],Out) -> Out;
 triangle_ls_lp([LS1|LSs1], [LS2|LSs2], Out) ->
-    {Y, Xl1, Xr1} = LS1,
-    {_, Xl2, Xr2} = LS2,
+    {Y, Xl1, Xr1, _Ca1} = LS1,
+    {_, Xl2, Xr2, _Ca2} = LS2,
     Xr = lists:max([Xl1,Xr1,Xl2,Xr2]),
     Xl = lists:min([Xl1,Xr1,Xl2,Xr2]),
-    triangle_ls_lp(LSs1, LSs2, [{Y,Xl,Xr}|Out]).    
+    triangle_ls_lp(LSs1,LSs2,[{Y,Xl,Xr}|Out]).
        
 tri_pt_ysort(Pts) ->
     % {X,Y}
@@ -414,9 +414,9 @@ tri_pt_ysort(Pts) ->
 	end, Pts).
 
 tri_ls_ysort(LSs) ->
-    % {Y, Xl, Xr}
+    % {Y, Xl, Xr, Ca}
     lists:sort(
-	fun ({Y1,_,_},{Y2,_,_}) ->
+	fun ({Y1,_,_,_},{Y2,_,_,_}) ->
 	   if Y1 > Y2 -> false; true -> true end
 	end, LSs).
 
@@ -503,69 +503,74 @@ point_inside_triangle(P, P1, P2, P3) ->
     points_same_side(P, P2, P1, P3) and 
     points_same_side(P, P3, P1, P2).
    
-%% [{Y, Xl, Xr}]
-ls_list2dict(List) -> ls_list2dict(List, dict:new()).
-ls_list2dict([], D) -> D;
-ls_list2dict([{Y, Xl, Xr}|Ls], D) ->
-    case dict:is_key(Y, D) of
-        false -> ls_list2dict(Ls, dict:store(Y, [{Xl, Xr}], D));
-	true  -> ls_list2dict(Ls, dict:append(Y, {Xl, Xr}, D))
-    end.
+%% [{Y, Xl, Xr}] -> #{Y := [{Xl,Xr}]}
+%% Reorganize linspans to a map with Y as key.
+
+linespans_to_map(Ls) ->
+    linespans_to_map(Ls,#{}).
+linespans_to_map([{Y,Xl,Xr,C}|Ls], M) ->
+    case M of
+        #{Y := Spans} -> linespans_to_map(Ls, M#{Y := [{Xl,Xr,C}|Spans]});
+        _ -> linespans_to_map(Ls, M#{Y => [{Xl,Xr,C}]})
+    end;
+linespans_to_map([], M) ->
+    M.
 
-%% line_ls
+
+%% line_to_linespans
+%%   Anti-aliased thick line
+%%   Do it CPS style
 %% In:
 %%	P1 :: point()
 %%	P2 :: point()
 %% Out:
-%%	{{Ymin,Ymax}, LSD :: line_step_data()}
-%% Purpose:
-%% 	Instead of points -> intervals
-
-
-line_ls({Xi0, Yi0},{Xi1,Yi1}) ->
-    % swap X with Y if line is steep
-    Steep = abs(Yi1 - Yi0) > abs(Xi1 - Xi0),
-
-    {Xs0, Ys0, Xs1, Ys1} = case Steep of
-	true -> {Yi0,Xi0,Yi1,Xi1};
-	false -> {Xi0,Yi0,Xi1,Yi1}
-    end,
-
-    {X0,Y0,X1,Y1} = case Xs0 > Xs1 of
-	true -> {Xs1,Ys1,Xs0,Ys0};
-	false -> {Xs0,Ys0,Xs1,Ys1}
-    end,
-
-    DX = X1 - X0,
-    DY = abs(Y1 - Y0),
-
-    Error = -DX/2,
-
-    Ystep = case Y0 < Y1 of
-	true -> 1;
-	false -> -1
-    end, 
-    line_ls_step(X0, X1,Y0, DX, DY, Ystep, Error, X0, Steep, []).
-
-%% line_ls_step_(not)_steep
-%% In:
-%% Out:
-%%	[{Yi, Xl,Xr}]
-%% Purpose:
-%% 	Produce an line_interval for each Yi (Y index)	
-
-line_ls_step(X, X1, Y, Dx, Dy, Ys, E, X0, false = Steep, LSs) when X < X1, E >= 0 ->
-    line_ls_step(X+1,X1,Y+Ys,Dx,Dy,Ys, E - Dx + Dy, X+1, Steep, [{Y,X0,X}|LSs]);
-line_ls_step(X, X1, Y, Dx, Dy, Ys, E, X0, false = Steep, LSs) when X < X1 ->
-    line_ls_step(X+1,X1,Y,Dx,Dy,Ys, E + Dy, X0, Steep, LSs);
-line_ls_step(X, _X1, Y, _Dx, _Dy, _Ys, _E, X0, false, LSs) ->
-    [{Y,X0,X}|LSs];
-line_ls_step(X, X1, Y, Dx, Dy, Ys, E, _X0, true = Steep, LSs) when X =< X1, E >= 0 ->
-    line_ls_step(X+1,X1,Y+Ys,Dx,Dy,Ys, E - Dx + Dy, X, Steep, [{X,Y,Y}|LSs]);
-line_ls_step(X, X1, Y, Dx, Dy, Ys, E, X0, true = Steep, LSs) when X =< X1 ->
-    line_ls_step(X+1,X1,Y,Dx,Dy,Ys,E + Dy, X0, Steep, [{X,Y,Y}|LSs]);
-line_ls_step(_X,_,_Y,_Dx,_Dy,_Ys,_E,_X0,_,LSs) -> 
-    LSs.
+%%      [{Y,Xl,Xr}]
+%%
+line_to_linespans({X0,Y0},{X1,Y1},Wd) ->
+    Dx = abs(X1-X0),
+    Dy = abs(Y1-Y0),
+    Sx = if X0 < X1 -> 1; true -> -1 end,
+    Sy = if Y0 < Y1 -> 1; true -> -1 end,
+    E0 = Dx - Dy,
+    Ed = if Dx + Dy =:= 0 -> 1; true -> math:sqrt(Dx*Dx + Dy*Dy) end,
+    line_to_ls(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E0,Ed,(Wd+1)/2,[]).
+
+line_to_ls(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls0) ->
+    C = max(0, 255*(abs(E - Dx+Dy)/Ed - Wd + 1)),
+    Ls1 = [{Y0,X0,X0,C}|Ls0],
+    line_to_ls_sx(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls1,E).
+
+line_to_ls_sx(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls,E2) when 2*E2 > -Dx ->
+    line_to_ls_sx_do(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls,E2+Dy,Y0);
+line_to_ls_sx(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls,E2) ->
+    line_to_ls_sy(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls,E2,X0).
+
+line_to_ls_sx_do(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls0,E2,Y) when E2 < Ed*Wd andalso
+                                                                (Y1 =/= Y orelse Dx > Dy) ->
+    Y2 = Y + Sy,
+    C = max(0,255*(abs(E2)/Ed-Wd+1)),
+    Ls = [{Y2,X0,X0,C}|Ls0],
+    line_to_ls_sx_do(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls,E2+Dx,Y2);
+line_to_ls_sx_do(X0,_Y0,X1,_Y1,_Dx,_Dy,_Sx,_Sy,_E,_Ed,_Wd,Ls,_E2,_Y) when X0 =:= X1 ->
+    Ls;
+line_to_ls_sx_do(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls,_E2,_Y) ->
+    line_to_ls_sy(X0+Sx,Y0,X1,Y1,Dx,Dy,Sx,Sy,E-Dy,Ed,Wd,Ls,E,X0).
+
+line_to_ls_sy(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls0,E2,X) when 2*E2 =< Dy ->
+    line_to_ls_sy_do(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls0,Dx-E2,X);
+line_to_ls_sy(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls0,_E2,_X) ->
+    line_to_ls(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls0).
+
+line_to_ls_sy_do(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls0,E2,X) when E2 < Ed*Wd andalso
+                                                                (X1 =/= X orelse Dx < Dy) ->
+    X2 = X + Sx,
+    C = max(0,255*(abs(E2)/Ed-Wd+1)),
+    Ls = [{Y0,X2,X2,C}|Ls0],
+    line_to_ls_sy_do(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls,E2+Dy,X2);
+line_to_ls_sy_do(_X0,Y0,_X1,Y1,_Dx,_Dy,_Sx,_Sy,_E,_Ed,_Wd,Ls,_E2,_X) when Y0 =:= Y1 ->
+    Ls;
+line_to_ls_sy_do(X0,Y0,X1,Y1,Dx,Dy,Sx,Sy,E,Ed,Wd,Ls0,_E2,_X) ->
+    line_to_ls(X0,Y0+Sy,X1,Y1,Dx,Dy,Sx,Sy,E+Dx,Ed,Wd,Ls0).
 
 % Text
 
diff --git a/lib/percept/test/egd_SUITE.erl b/lib/percept/test/egd_SUITE.erl
index 3562ceae88..401695dddd 100644
--- a/lib/percept/test/egd_SUITE.erl
+++ b/lib/percept/test/egd_SUITE.erl
@@ -32,6 +32,7 @@
          image_primitives/1,
          image_colors/1,
          image_font/1,
+         image_fans/1,
          image_png_compliant/1]).
 
 suite() ->
@@ -41,6 +42,7 @@ suite() ->
 all() -> 
     [image_create_and_destroy, image_shape,
      image_primitives, image_colors, image_font,
+     image_fans,
      image_png_compliant].
 
 
@@ -71,6 +73,7 @@ image_create_and_destroy(Config) when is_list(Config) ->
 %% Image color test.
 image_colors(Config) when is_list(Config) ->
     {W,H} = get_size(proplists:get_value(max_size, Config)),
+    Dir = proplists:get_value(priv_dir, Config),
     Image = egd:create(W, H),
     put(image_size, {W,H}),
 
@@ -96,7 +99,15 @@ image_colors(Config) when is_list(Config) ->
                           ok    = egd:line(Image, get_point(), get_point(), Color)
                   end, HtmlDefaultNames),
 
-    <<_/binary>>  = egd:render(Image),
+    Png1 = <<_/binary>> = egd:render(Image,png,[{render_engine, alpha}]),
+    File1 = filename:join(Dir,"image_colors_alpha.png"),
+    ok = egd:save(Png1,File1),
+    ct:log("<p>Image alpha:</p><img src=\"~s\" />~n", [File1]),
+    Png2 = <<_/binary>> = egd:render(Image,png,[{render_engine, opaque}]),
+    File2 = filename:join(Dir,"image_colors_opaque.png"),
+    ok = egd:save(Png2,File2),
+    ct:log("<p>Image opaque:</p><img src=\"~s\" />~n", [File2]),
+
     ok = egd:destroy(Image),
     erase(image_size),
     ok.
@@ -104,6 +115,7 @@ image_colors(Config) when is_list(Config) ->
 %% Image shape API test.
 image_shape(Config) when is_list(Config) ->
     {W,H} = get_size(proplists:get_value(max_size, Config)),
+    Dir = proplists:get_value(priv_dir, Config),
     put(image_size, {W,H}),
     Im = egd:create(W, H),
 
@@ -125,15 +137,21 @@ image_shape(Config) when is_list(Config) ->
     ok = bitmap_point_has_color(Bitmap, {W,H}, Pt2, Fgc),
     ok = bitmap_point_has_color(Bitmap, {W,H}, Pt1, Fgc),
 
-    <<_/binary>> = egd:render(Im, raw_bitmap, [{render_engine, alpha}]),
+    Bin = <<_/binary>> = egd:render(Im, raw_bitmap, [{render_engine, alpha}]),
+    Png = egd_png:binary(W,H,Bin),
+    File = filename:join(Dir,"image_shape.png"),
+    ok = egd:save(Png,File),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File]),
 
     ok = egd:destroy(Im),
+
     erase(image_size),
     ok.
 
 %% Image shape API test.
 image_primitives(Config) when is_list(Config) ->
     {W,H} = get_size(proplists:get_value(max_size, Config)),
+    Dir = proplists:get_value(priv_dir, Config),
     put(image_size, {W,H}),
 
     Im0 = egd_primitives:create(W, H),
@@ -157,7 +175,11 @@ image_primitives(Config) when is_list(Config) ->
     ok = bitmap_point_has_color(Bitmap, {W,H}, Pt2, Fgc),
     ok = bitmap_point_has_color(Bitmap, {W,H}, Pt1, Fgc),
 
-    <<_/binary>> = egd_render:binary(Im2, alpha),
+    Bin = <<_/binary>> = egd_render:binary(Im2, alpha),
+    Png = egd_png:binary(W,H,Bin),
+    File = filename:join(Dir,"image_primitives.png"),
+    ok = egd:save(Png,File),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File]),
 
     erase(image_size),
     ok.
@@ -165,6 +187,7 @@ image_primitives(Config) when is_list(Config) ->
 %% Image font test.
 image_font(Config) when is_list(Config) ->
     {W,H} = get_size(proplists:get_value(max_size, Config)),
+    Dir = proplists:get_value(priv_dir, Config),
     put(image_size, {W,H}),
     Im = egd:create(W, H),
     Fgc = egd:color({0,130,0}),
@@ -185,25 +208,46 @@ image_font(Config) when is_list(Config) ->
     GlyphStr4   = "{|}~",                         % Codes 123 -> 126
 
     ok = egd:text(Im, get_point(), Font, GlyphStr1, Fgc),
-    <<_/binary>> = egd:render(Im, png),
+    Png1 = <<_/binary>> = egd:render(Im, png),
+    File1 = filename:join(Dir,"text1.png"),
+    ok = egd:save(Png1,File1),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File1]),
 
     ok = egd:text(Im, get_point(), Font, NumericStr, Fgc),
-    <<_/binary>> = egd:render(Im, png),
+    Png2 = <<_/binary>> = egd:render(Im, png),
+    File2 = filename:join(Dir,"text2.png"),
+    ok = egd:save(Png2,File2),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File2]),
 
     ok = egd:text(Im, get_point(), Font, GlyphStr2, Fgc),
-    <<_/binary>> = egd:render(Im, png),
+    Png3 = <<_/binary>> = egd:render(Im, png),
+    File3 = filename:join(Dir,"text3.png"),
+    ok = egd:save(Png3,File3),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File3]),
 
     ok = egd:text(Im, get_point(), Font, AlphaBigStr, Fgc),
-    <<_/binary>> = egd:render(Im, png),
+    Png4 = <<_/binary>> = egd:render(Im, png),
+    File4 = filename:join(Dir,"text4.png"),
+    ok = egd:save(Png4,File4),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File4]),
 
     ok = egd:text(Im, get_point(), Font, GlyphStr3, Fgc),
-    <<_/binary>> = egd:render(Im, png),
+    Png5 = <<_/binary>> = egd:render(Im, png),
+    File5 = filename:join(Dir,"text5.png"),
+    ok = egd:save(Png5,File5),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File5]),
 
     ok = egd:text(Im, get_point(), Font, AlphaSmStr, Fgc),
-    <<_/binary>> = egd:render(Im, png),
+    Png6 = <<_/binary>> = egd:render(Im, png),
+    File6 = filename:join(Dir,"text6.png"),
+    ok = egd:save(Png6,File6),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File6]),
 
     ok = egd:text(Im, get_point(), Font, GlyphStr4, Fgc),
-    <<_/binary>> = egd:render(Im, png),
+    Png7 = <<_/binary>> = egd:render(Im, png),
+    File7 = filename:join(Dir,"text7.png"),
+    ok = egd:save(Png7,File7),
+    ct:log("<p>Image:</p><img src=\"~s\" />~n", [File7]),
 
     ok = egd:destroy(Im),
     erase(image_size),
@@ -224,6 +268,65 @@ image_png_compliant(Config) when is_list(Config) ->
     erase(image_size),
     ok.
 
+image_fans(Config) when is_list(Config) ->
+    W = 1024,
+    H = 800,
+    Dir = proplists:get_value(priv_dir, Config),
+
+    Fun = fun({F,Args},Im) ->
+                  erlang:apply(egd_primitives,F,[Im|Args])
+          end,
+
+    %% fan1
+    Ops1 = gen_vertical_fan(1,{0,400},egd:color(red),1024,800,-15),
+    Ops2 = gen_horizontal_fan(1,{512,800},egd:color(green),1024,0,-15),
+
+    Im0 = egd_primitives:create(W,H),
+    Im1 = lists:foldl(Fun, Im0, Ops1 ++ Ops2),
+    Bin1 = egd_render:binary(Im1, opaque),
+    Png1 = egd_png:binary(W,H,Bin1),
+
+    File1 = filename:join(Dir,"fan1_opaque.png"),
+    ok = egd:save(Png1,File1),
+    ct:log("<p>Image opaque width 1:</p><img src=\"~s\" />~n", [File1]),
+
+    Bin2 = egd_render:binary(Im1, alpha),
+    Png2 = egd_png:binary(W,H,Bin2),
+
+    File2 = filename:join(Dir,"fan1_alpha.png"),
+    ok = egd:save(Png2,File2),
+    ct:log("<p>Image alpha width 1:</p><img src=\"~s\" />~n", [File2]),
+
+
+    %% fan2
+    Ops3 = gen_vertical_fan(7,{0,400},egd:color(red),1024,800,-15),
+    Ops4 = gen_horizontal_fan(7,{512,800},egd:color(green),1024,0,-15),
+
+    Im2 = lists:foldl(Fun, Im0, Ops3 ++ Ops4),
+    Bin3 = egd_render:binary(Im2, opaque),
+    Png3 = egd_png:binary(W,H,Bin3),
+
+    File3 = filename:join(Dir,"fan2_opaque.png"),
+    ok = egd:save(Png3,File3),
+    ct:log("<p>Image opaque width 7:</p><img src=\"~s\" />~n", [File3]),
+
+    Bin4 = egd_render:binary(Im2, alpha),
+    Png4 = egd_png:binary(W,H,Bin4),
+
+    File4 = filename:join(Dir,"fan2_alpha.png"),
+    ok = egd:save(Png4,File4),
+    ct:log("<p>Image alpha width 7:</p><img src=\"~s\" />~n", [File4]),
+    ok.
+
+gen_vertical_fan(Wd,Pt,C,X,Y,Step) when Y > 0 ->
+    [{line,[Pt,{X,Y},Wd,C]}|gen_vertical_fan(Wd,Pt,C,X,Y + Step,Step)];
+gen_vertical_fan(_,_,_,_,_,_) -> [].
+
+gen_horizontal_fan(Wd,Pt,C,X,Y,Step) when X > 0 ->
+    [{line,[Pt,{X,Y},Wd,C]}|gen_horizontal_fan(Wd,Pt,C,X + Step,Y,Step)];
+gen_horizontal_fan(_,_,_,_,_,_) -> [].
+
+
 %%----------------------------------------------------------------------
 %% Auxiliary tests
 %%----------------------------------------------------------------------
@@ -239,33 +342,6 @@ bitmap_point_has_color(Bitmap, {W,_}, {X,Y}, C) ->
             {error, {Other,{CR,CG,CB}}}
     end.
 
-%% jfif header by specification
-%% 2 bytes, length
-%% 5 bytes, identifier ="JFIF\0"
-%% 2 bytes, version, (major, minor)
-%% 1 byte , units
-%% However, JFIF seems to start at 6 (7 with 1-index)?
-
-binary_is_jfif_compliant(JpegBin) ->
-    {Bin, _} = split_binary(JpegBin, 11),
-    List = binary_to_list(Bin),
-    case lists:sublist(List, 7, 4) of 
-        "JFIF" -> true;
-        Other ->
-            io:format("img -> ~p~n", [Other]),
-            false
-    end.
-
-binary_is_gif_compliant(GifBin) ->
-    {Bin, _} = split_binary(GifBin, 10),
-    List = binary_to_list(Bin),
-    case lists:sublist(List, 1,5) of
-        "GIF87" -> true;
-        Other ->
-            io:format("img -> ~p~n", [Other]),
-            false
-    end.
-
 binary_is_png_compliant(PngBin) ->
     {Bin, _} = split_binary(PngBin, 10),
     List = binary_to_list(Bin),