some fixes (#87) (#90)

* FIX: perlin.red cannot be compiled.

* FIX: disable Draw button while image is processing.

* FEAT: minor improvements in ballots demo.

Author: qtxie

Scripts/mandelbrot.red

@@ -26,12 +26,11 @@ mandelIter: function [cx cy maxIter][
 ]
 
 mandelbrot: function [img xmin xmax ymin ymax iterations][
+	img/image/argb: white
 	width:  img/image/size/x
 	height: img/image/size/y
 	pix:	img/image/rgb
 
-	img/image/rgb: white
-	
 	iy: 0
 	while [iy < height] [
 		ix: 0
@@ -74,8 +73,10 @@ view [
 	]
 	button "Draw" 150x40 [
 		t0: now/time/precise
+		face/enabled?: no
 		mandelbrot img xmin/data xmax/data ymin/data ymax/data iterations/data
 		dt/data: round now/time/precise - t0
+		face/enabled?: yes
 	]
 	across txt "time (s):" dt: txt
 	below return

Scripts/perlin.red

@@ -96,7 +96,7 @@ gen-texture: routine [
 			-y: -y + 1
 			yy: yy + coeff
 			if 255.0 < yy [
-				yy: yy % 255.0
+				yy: fmod yy 255.0
 				y: y + 1
 			]
 
@@ -112,7 +112,7 @@ gen-texture: routine [
 				-x: -x + 1
 				xx: xx + coeff
 				if 255.0 < xx [
-					xx: xx % 255.0
+					xx: fmod xx 255.0
 					x: x + 1
 				]
 

Showcase/ballots/ballots.red

@@ -61,13 +61,13 @@ shapes: [
 		line 13x29 27x29
 	]
 	circle: [
-		at 0x0 person draw [
+		at 0x0 base transparent draw [
 			pen gray fill-pen off
 			line-width 4 disk: circle -1x-1 100
 		] 260x260
 	]
 	circles: [
-		at 0x0 person draw [
+		at 0x0 base transparent draw [
 			pen gray fill-pen off disks:
 			line-width 1 circle -1x-1 120
 			line-width 2 circle -1x-1 90