diff --git a/core/src/main/common/org/isoron/platform/gui/Image.kt b/core/src/main/common/org/isoron/platform/gui/Image.kt
index 4f9c41302..044df1c6f 100644
--- a/core/src/main/common/org/isoron/platform/gui/Image.kt
+++ b/core/src/main/common/org/isoron/platform/gui/Image.kt
@@ -31,8 +31,8 @@ interface Image {
     suspend fun export(path: String)
 
     fun diff(other: Image) {
-        if (width != other.width) error("Width must match")
-        if (height != other.height) error("Height must match")
+        if (width != other.width) error("Width must match: $width !== ${other.width}")
+        if (height != other.height) error("Height must match: $height !== ${other.height}")
 
         for (x in 0 until width) {
             for (y in 0 until height) {
diff --git a/core/src/main/ios/org/isoron/platform/gui/IosCanvas.kt b/core/src/main/ios/org/isoron/platform/gui/IosCanvas.kt
index c8f2e6871..35293a284 100644
--- a/core/src/main/ios/org/isoron/platform/gui/IosCanvas.kt
+++ b/core/src/main/ios/org/isoron/platform/gui/IosCanvas.kt
@@ -28,8 +28,12 @@ val Color.uicolor: UIColor
 val Color.cgcolor: CGColorRef?
     get() = uicolor.CGColor
 
-class IosCanvas(val ctx: CGContextRef) : Canvas {
+class IosCanvas(val width: Double,
+                val height: Double,
+                val pixelScale: Double = 2.0
+               ) : Canvas {
     var textColor = UIColor.blackColor
+    val ctx = UIGraphicsGetCurrentContext()!!
 
     override fun setColor(color: Color) {
         CGContextSetStrokeColorWithColor(ctx, color.cgcolor)
@@ -38,32 +42,47 @@ class IosCanvas(val ctx: CGContextRef) : Canvas {
     }
 
     override fun drawLine(x1: Double, y1: Double, x2: Double, y2: Double) {
+        CGContextMoveToPoint(ctx, x1 * pixelScale, y1 * pixelScale)
+        CGContextAddLineToPoint(ctx, x2 * pixelScale, y2 * pixelScale)
+        CGContextStrokePath(ctx)
     }
 
     override fun drawText(text: String, x: Double, y: Double) {
     }
 
     override fun fillRect(x: Double, y: Double, width: Double, height: Double) {
+        CGContextFillRect(ctx,
+                          CGRectMake(x * pixelScale,
+                                     y * pixelScale,
+                                     width * pixelScale,
+                                     height * pixelScale))
     }
 
     override fun drawRect(x: Double, y: Double, width: Double, height: Double) {
+        CGContextStrokeRect(ctx,
+                            CGRectMake(x * pixelScale,
+                                       y * pixelScale,
+                                       width * pixelScale,
+                                       height * pixelScale))
     }
 
     override fun getHeight(): Double {
-        return 0.0
+        return height
     }
 
     override fun getWidth(): Double {
-        return 0.0
+        return width
     }
 
     override fun setFont(font: Font) {
     }
 
     override fun setFontSize(size: Double) {
+        CGContextSetFontSize(ctx, size * pixelScale)
     }
 
     override fun setStrokeWidth(size: Double) {
+        CGContextSetLineWidth(ctx, size * pixelScale)
     }
 
     override fun fillArc(centerX: Double,
@@ -80,6 +99,6 @@ class IosCanvas(val ctx: CGContextRef) : Canvas {
     }
 
     override fun toImage(): Image {
-        TODO()
+        return IosImage(UIGraphicsGetImageFromCurrentImageContext()!!)
     }
-}
\ No newline at end of file
+}
diff --git a/core/src/main/ios/org/isoron/platform/gui/IosImage.kt b/core/src/main/ios/org/isoron/platform/gui/IosImage.kt
new file mode 100644
index 000000000..33e1c2254
--- /dev/null
+++ b/core/src/main/ios/org/isoron/platform/gui/IosImage.kt
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2016-2019 Álinson Santos Xavier <isoron@gmail.com>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.platform.gui
+
+import platform.UIKit.*
+import platform.CoreGraphics.*
+import platform.Foundation.*
+
+class IosImage(val image: UIImage) : Image {
+
+    override val width: Int
+        get() {
+            return CGImageGetWidth(image.CGImage).toInt()
+        }
+
+    override val height: Int
+        get() {
+            return CGImageGetHeight(image.CGImage).toInt()
+        }
+
+    override fun getPixel(x: Int, y: Int): Color {
+        return Color(1.0, 0.0, 0.0, 1.0)
+    }
+
+    override fun setPixel(x: Int, y: Int, color: Color) {
+    }
+
+    @Suppress("CAST_NEVER_SUCCEEDS")
+    override suspend fun export(path: String) {
+        val tmpPath = "${NSTemporaryDirectory()}/$path"
+        val dir = (tmpPath as NSString).stringByDeletingLastPathComponent
+        NSFileManager.defaultManager.createDirectoryAtPath(dir, true, null, null)
+        val data = UIImagePNGRepresentation(image)!!
+        val success = data.writeToFile(tmpPath, true)
+        if (!success) throw RuntimeException("could not write to $tmpPath")
+        println(tmpPath)
+    }
+}
\ No newline at end of file
diff --git a/core/src/main/ios/org/isoron/platform/io/IosFiles.kt b/core/src/main/ios/org/isoron/platform/io/IosFiles.kt
index 4a2f3c85a..16d189133 100644
--- a/core/src/main/ios/org/isoron/platform/io/IosFiles.kt
+++ b/core/src/main/ios/org/isoron/platform/io/IosFiles.kt
@@ -22,6 +22,7 @@ package org.isoron.platform.io
 
 import org.isoron.platform.gui.*
 import platform.Foundation.*
+import platform.UIKit.*
 
 class IosFileOpener : FileOpener {
     override fun openResourceFile(path: String): ResourceFile {
@@ -62,6 +63,6 @@ class IosFile(val path: String) : UserFile, ResourceFile {
     }
 
     override suspend fun toImage(): Image {
-        TODO()
+        return IosImage(UIImage.imageWithContentsOfFile(path)!!)
     }
 }
\ No newline at end of file
diff --git a/core/src/test/common/org/isoron/platform/gui/CanvasTest.kt b/core/src/test/common/org/isoron/platform/gui/CanvasTest.kt
index d4ab43f8d..1c2065cde 100644
--- a/core/src/test/common/org/isoron/platform/gui/CanvasTest.kt
+++ b/core/src/test/common/org/isoron/platform/gui/CanvasTest.kt
@@ -24,7 +24,7 @@ import org.isoron.uhabits.*
 import kotlin.test.*
 
 class CanvasTest: BaseViewTest() {
-    //@Test
+    @Test
     fun run() = asyncTest{
         val canvas = DependencyResolver.createCanvas(500, 400)
 
diff --git a/core/src/test/ios/org/isoron/DependencyResolver.kt b/core/src/test/ios/org/isoron/DependencyResolver.kt
index 9227991ce..0044336af 100644
--- a/core/src/test/ios/org/isoron/DependencyResolver.kt
+++ b/core/src/test/ios/org/isoron/DependencyResolver.kt
@@ -19,6 +19,7 @@
 
 package org.isoron
 
+import kotlinx.cinterop.*
 import org.isoron.platform.gui.*
 import org.isoron.platform.io.*
 import org.isoron.platform.time.*
@@ -37,9 +38,9 @@ actual object DependencyResolver {
     }
 
     actual fun createCanvas(width: Int, height: Int): Canvas {
-        UIGraphicsBeginImageContext(CGSizeMake(width.toDouble(), height.toDouble()))
-        val ctx = UIGraphicsGetCurrentContext()!!
-        return IosCanvas(ctx)
+        val scale = 2.0
+        UIGraphicsBeginImageContext(CGSizeMake(width * scale, height * scale))
+        return IosCanvas(width * scale, height * scale, pixelScale = scale)
     }
 
     actual suspend fun getDatabase(): Database {