diff --git a/PanoPainter/GameViewController.m b/PanoPainter/GameViewController.m
index d66940e..1e5f101 100644
--- a/PanoPainter/GameViewController.m
+++ b/PanoPainter/GameViewController.m
@@ -157,6 +157,7 @@ int t_count = 0;
 
 - (void)viewDidAppear:(BOOL)animated
 {
+    App::I.redraw = true;
     [self resignFirstResponder];
     [self registerForKeyboardNotifications];
 }
@@ -235,6 +236,8 @@ int t_count = 0;
 
 - (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
 {
+    if (!App::I.redraw)
+        return;
     App::I.clear();
     App::I.update(0);
 }
diff --git a/PanoPainter/Info.plist b/PanoPainter/Info.plist
index 44468d2..90b2ea6 100644
--- a/PanoPainter/Info.plist
+++ b/PanoPainter/Info.plist
@@ -2,6 +2,8 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+	<key>NSPhotoLibraryAddUsageDescription</key>
+	<string>Save the pano image in the user gallery</string>
 	<key>CFBundleDevelopmentRegion</key>
 	<string>en</string>
 	<key>CFBundleExecutable</key>
diff --git a/data/layout.xml b/data/layout.xml
index 9586553..e36854d 100644
--- a/data/layout.xml
+++ b/data/layout.xml
@@ -353,6 +353,7 @@
         </button-custom>
         <button id="btn-undo" width="50" height="100%" margin="0 5 0 0" text="Undo"/>
         <button id="btn-pen" width="50" height="100%" margin="0 0 0 0" text="Pen"/>
+        <button id="btn-pick" width="50" height="100%" margin="0 0 0 0" text="Pick"/>
         <button id="btn-erase" width="60" height="100%" margin="0 0 0 0" text="Erase"/>
         <button id="btn-line" width="50" height="100%" margin="0 0 0 0" text="Line"/>
         <button id="btn-cam" width="70" height="100%" margin="0 0 0 0" text="Camera"/>
diff --git a/engine.xcodeproj/project.pbxproj b/engine.xcodeproj/project.pbxproj
index 4ef9843..f4382b4 100644
--- a/engine.xcodeproj/project.pbxproj
+++ b/engine.xcodeproj/project.pbxproj
@@ -278,7 +278,7 @@
 		AD4C08D21E89BD0F0051D85F /* bezier.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = bezier.h; sourceTree = "<group>"; };
 		AD4C08D31E89BD0F0051D85F /* brush.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = brush.cpp; sourceTree = "<group>"; };
 		AD4C08D41E89BD0F0051D85F /* brush.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = brush.h; sourceTree = "<group>"; };
-		AD4C08D51E89BD0F0051D85F /* canvas.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = canvas.cpp; sourceTree = "<group>"; };
+		AD4C08D51E89BD0F0051D85F /* canvas.cpp */ = {isa = PBXFileReference; explicitFileType = sourcecode.cpp.objcpp; fileEncoding = 4; path = canvas.cpp; sourceTree = "<group>"; };
 		AD4C08D61E89BD0F0051D85F /* canvas.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = canvas.h; sourceTree = "<group>"; };
 		AD4C08D71E89BD0F0051D85F /* rtt.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = rtt.cpp; sourceTree = "<group>"; };
 		AD4C08D81E89BD0F0051D85F /* rtt.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = rtt.h; sourceTree = "<group>"; };
diff --git a/engine/app.cpp b/engine/app.cpp
index da451fd..0fee77a 100644
--- a/engine/app.cpp
+++ b/engine/app.cpp
@@ -88,7 +88,8 @@ void App::init()
 
     LOG("Screen Resolution: %dx%d", (int)width, (int)height);
 
-    zoom = ceilf(width / 2000.f);
+    //zoom = ceilf(width / 2000.f);
+    //zoom = 2;
     
 #ifdef __IOS__
     NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
@@ -119,6 +120,9 @@ void App::update(float dt)
     // update offscreen stuff
     if (canvas && canvas->m_canvas)
         canvas->m_canvas->stroke_draw();
+    
+    if (!redraw)
+        return;
 
     //glClearColor(.1f, .1f, .1f, 1.f);
     //glViewport(0, 0, (GLsizei)width, (GLsizei)height);
@@ -129,6 +133,13 @@ void App::update(float dt)
 #endif
     if (auto* main = layout[main_id])
         main->update(width, height, zoom);
+    
+    static glm::vec4 color_button_normal{.1, .1, .1, 1};
+    static glm::vec4 color_button_hlight{ 1, .0, .0, 1};
+    CanvasModePen* mode = (CanvasModePen*)canvas->m_canvas->modes[(int)Canvas::kCanvasMode::Draw][0];
+    layout[main_id]->find<NodeButton>("btn-pick")->set_color(
+         mode->m_picking ? color_button_hlight : color_button_normal);
+
 
     auto observer = [this](Node* n)
     {
@@ -145,7 +156,9 @@ void App::update(float dt)
     if (auto* main = layout[main_id])
         main->watch(observer);
     //msgbox->watch(observer);
-    glDisable(GL_SCISSOR_TEST); 
+    glDisable(GL_SCISSOR_TEST);
+    
+    redraw = false;
 }
 
 
diff --git a/engine/app.h b/engine/app.h
index ccceb2e..62ae67a 100644
--- a/engine/app.h
+++ b/engine/app.h
@@ -49,10 +49,13 @@ public:
     float width;
     float height;
     bool keys[256];
+    bool redraw = true;
     glm::vec2 gesture_p0;
     glm::vec2 gesture_p1;
 #ifdef __ANDROID__
     float zoom = 3.0;
+#elif __IOS__
+    float zoom = 2.0;
 #else
     float zoom = 1.0;
 #endif // __ANDROID__
diff --git a/engine/app_events.cpp b/engine/app_events.cpp
index 6e47880..5019996 100644
--- a/engine/app_events.cpp
+++ b/engine/app_events.cpp
@@ -5,6 +5,7 @@ using namespace ui;
 
 void App::resize(float w, float h)
 {
+    redraw = true;
     width = w;
     height = h;
     if (auto* main = layout[main_id])
@@ -13,6 +14,7 @@ void App::resize(float w, float h)
 
 void App::showKeyboard()
 {
+    redraw = true;
 #ifdef __IOS__
     [ios_view becomeFirstResponder];
 #endif
@@ -20,6 +22,7 @@ void App::showKeyboard()
 
 void App::hideKeyboard()
 {
+    redraw = true;
 #ifdef __IOS__
     [ios_view resignFirstResponder];
 #endif
@@ -27,6 +30,7 @@ void App::hideKeyboard()
 
 bool App::mouse_down(int button, float x, float y, float pressure)
 {
+    redraw = true;
     MouseEvent e;
     e.m_type = button ? kEventType::MouseDownR : kEventType::MouseDownL;
     e.m_pos = { x / zoom, y / zoom };
@@ -37,6 +41,7 @@ bool App::mouse_down(int button, float x, float y, float pressure)
 }
 bool App::mouse_move(float x, float y, float pressure)
 {
+    redraw = true;
     MouseEvent e;
     e.m_type = kEventType::MouseMove;
     e.m_pos = { x / zoom, y / zoom };
@@ -48,6 +53,7 @@ bool App::mouse_move(float x, float y, float pressure)
 }
 bool App::mouse_up(int button, float x, float y)
 {
+    redraw = true;
     MouseEvent e;
     e.m_type = button ? kEventType::MouseUpR : kEventType::MouseUpL;
     e.m_pos = { x / zoom, y / zoom };
@@ -57,6 +63,7 @@ bool App::mouse_up(int button, float x, float y)
 }
 bool App::mouse_scroll(float x, float y, float delta)
 {
+    redraw = true;
     MouseEvent e;
     e.m_type = kEventType::MouseScroll;
     e.m_pos = { x / zoom, y / zoom };
@@ -67,6 +74,7 @@ bool App::mouse_scroll(float x, float y, float delta)
 }
 bool App::mouse_cancel(int button)
 {
+    redraw = true;
     MouseEvent e;
     e.m_type = kEventType::MouseCancel;
     auto ret = layout[main_id]->on_event(&e);
@@ -75,6 +83,7 @@ bool App::mouse_cancel(int button)
 }
 bool App::gesture_start(const glm::vec2& p0, const glm::vec2& p1)
 {
+    redraw = true;
     GestureEvent e;
     glm::vec2 p = glm::lerp(p0, p1, 0.5f);
     e.m_type = kEventType::GestureStart;
@@ -88,6 +97,7 @@ bool App::gesture_start(const glm::vec2& p0, const glm::vec2& p1)
 }
 bool App::gesture_move(const glm::vec2& p0, const glm::vec2& p1)
 {
+    redraw = true;
     GestureEvent e;
     glm::vec2 p = glm::lerp(p0, p1, 0.5f);
     e.m_type = kEventType::GestureMove;
@@ -101,6 +111,7 @@ bool App::gesture_move(const glm::vec2& p0, const glm::vec2& p1)
 }
 bool App::gesture_end()
 {
+    redraw = true;
     GestureEvent e;
     e.m_type = kEventType::GestureEnd;
     auto ret = layout[main_id]->on_event(&e);
@@ -109,6 +120,7 @@ bool App::gesture_end()
 }
 bool App::key_down(kKey key)
 {
+    redraw = true;
     keys[(int)key] = true;
     KeyEvent e;
     e.m_type = kEventType::KeyDown;
@@ -119,6 +131,7 @@ bool App::key_down(kKey key)
 }
 bool App::key_up(kKey key)
 {
+    redraw = true;
     keys[(int)key] = false;
     KeyEvent e;
     e.m_type = kEventType::KeyUp;
@@ -129,6 +142,7 @@ bool App::key_up(kKey key)
 }
 bool App::key_char(char key)
 {
+    redraw = true;
     KeyEvent e;
     e.m_type = kEventType::KeyChar;
     e.m_char = key;
diff --git a/engine/app_layout.cpp b/engine/app_layout.cpp
index d169e07..2e88afd 100644
--- a/engine/app_layout.cpp
+++ b/engine/app_layout.cpp
@@ -127,6 +127,16 @@ void App::initLayout()
             layout[main_id]->find<NodeButton>("btn-pen")->set_color(color_button_hlight);
             Canvas::set_mode(Canvas::kCanvasMode::Draw);
         }
+        if (auto* button = layout[main_id]->find<NodeButton>("btn-pick"))
+        {
+            button->on_click = [this](Node*) {
+                CanvasModePen* mode = (CanvasModePen*)canvas->m_canvas->modes[(int)Canvas::kCanvasMode::Draw][0];
+                if (mode)
+                {
+                    mode->m_picking = true;
+                }
+            };
+        }
         if (auto* button = layout[main_id]->find<NodeButton>("btn-erase"))
         {
             button->on_click = [this](Node*) {
diff --git a/engine/canvas.cpp b/engine/canvas.cpp
index 225dad4..ec48732 100644
--- a/engine/canvas.cpp
+++ b/engine/canvas.cpp
@@ -2,6 +2,11 @@
 #include "log.h"
 #include "canvas.h"
 
+#ifdef __APPLE__
+#include <Foundation/Foundation.h>
+#endif
+
+
 ui::Canvas* ui::Canvas::I;
 std::vector<CanvasMode*> ui::Canvas::modes[] = {
     { new CanvasModePen, new CanvasModeBasicCamera },
@@ -44,6 +49,91 @@ glm::mat4 ui::Canvas::m_plane_transform[6] = {
     glm::lookAt(glm::vec3(), { 0,-1, 0}, {0, 0, 1}), // bottom
 };
 
+void ui::Canvas::pick_start()
+{
+    for (int i = 0; i < 6; i++)
+        m_pick_ready[i] = false;
+}
+void ui::Canvas::pick_update(int plane)
+{
+    // check if already updated
+    if (m_pick_ready[plane])
+        return;
+    
+    // save viewport and clear color states
+    GLint vp[4];
+    GLfloat cc[4];
+    glGetIntegerv(GL_VIEWPORT, vp);
+    glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);
+    GLboolean blend = glIsEnabled(GL_BLEND);
+    
+    // prepare common states
+    glViewport(0, 0, m_width, m_height);
+    glDisable(GL_BLEND);
+    
+    //for (int i = 0; i < 6; i++)
+    {
+        int i = plane;
+        m_tmp[i].bindFramebuffer();
+        m_tmp[i].clear({ 1, 1, 1, 1 });
+        
+        for (auto layer_index : m_order)
+        {
+            // copy to tmp2 for layer blending
+            glActiveTexture(GL_TEXTURE0); // TODO: maybe remove this line
+            m_tex2[i].bind();
+            glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, m_width, m_height);
+            m_tex2[i].unbind();
+            
+            m_layers[layer_index].m_rtt[i].bindTexture();
+            glActiveTexture(GL_TEXTURE1);
+            m_tex2[i].bind();
+            m_sampler.bind(0);
+            m_sampler_bg.bind(1);
+            ShaderManager::use(ui::kShader::StrokeLayer);
+            ShaderManager::u_int(kShaderUniform::TexBG, 1);
+            ShaderManager::u_float(kShaderUniform::Alpha, m_layers[layer_index].m_opacity);
+            ShaderManager::u_int(kShaderUniform::Tex, 0);
+            ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-.5f, .5f, -.5f, .5f, -1.f, 1.f));
+            m_plane.draw_fill();
+            m_sampler.unbind();
+            m_sampler_bg.unbind();
+            m_tex2[i].unbind();
+            m_layers[layer_index].m_rtt[i].unbindTexture();
+        }
+        if (!m_pick_data[plane])
+            m_pick_data[plane] = std::make_unique<glm::u8vec4[]>(m_width*m_height);
+        glReadPixels(0, 0, m_width, m_height, GL_RGBA, GL_UNSIGNED_BYTE, m_pick_data[plane].get());
+        LOG("read plane %d", plane);
+        m_tmp[i].unbindFramebuffer();
+    }
+    
+    // restore viewport and clear color states
+    blend ? glEnable(GL_BLEND) : glDisable(GL_BLEND);
+    glViewport(vp[0], vp[1], vp[2], vp[3]);
+    glClearColor(cc[0], cc[1], cc[2], cc[3]);
+    glActiveTexture(GL_TEXTURE0);
+
+    
+    m_pick_ready[plane] = true;
+}
+glm::vec4 ui::Canvas::pick_get(glm::vec2 canvas_loc)
+{
+    glm::vec3 ray_origin;
+    glm::vec3 ray_dir;
+    glm::vec3 hit_pos;
+    glm::vec3 hit_normal;
+    int plane_id;
+    if (point_trace(canvas_loc, ray_origin, ray_dir, hit_pos, hit_normal, plane_id))
+    {
+        pick_update(plane_id);
+        glm::vec2 fbpos = (hit_pos.xy() * 0.5f + 0.5f) * glm::vec2(m_width, m_height);
+        LOG("pick plane %d x %d y %d", plane_id, (int)fbpos.x, (int)fbpos.y);
+        int i = fbpos.x + fbpos.y * m_width;
+        return glm::vec4(m_pick_data[plane_id][i]) / 255.f;
+    }
+    return {0,0,0,1};
+}
 void ui::Canvas::clear(const glm::vec4& c/*={0,0,0,1}*/)
 {
     snap_history({ 0, 1, 2, 3, 4, 5 });
@@ -558,6 +648,9 @@ void ui::Canvas::clear_context()
     }
 };
 
+#ifdef __IOS__
+UIImage *image;
+#endif
 void ui::Canvas::export_equirectangular(std::string data_path)
 {
     // save viewport and clear color states
@@ -657,6 +750,10 @@ void ui::Canvas::export_equirectangular(std::string data_path)
         params.m_quality = 100;
         bool saved = jpge::compress_image_to_jpeg_file(name, m_latlong.getWidth(), m_latlong.getHeight(), 4, latlong_data.get(), params);
         //int ret = stbi_write_png(name, m_latlong.getWidth(), m_latlong.getHeight(), 4, latlong_data.get(), m_latlong.stride());
+#ifdef __IOS__
+        image = [UIImage imageWithContentsOfFile:[NSString stringWithUTF8String:name]];
+        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
+#endif
     }
 
     glDeleteTextures(1, &cube_id);
diff --git a/engine/canvas.h b/engine/canvas.h
index 641393b..3ec472c 100644
--- a/engine/canvas.h
+++ b/engine/canvas.h
@@ -65,6 +65,8 @@ public:
     RTT m_tmp[6];
     Texture2D m_tex[6];
     Texture2D m_tex2[6];
+    bool m_pick_ready[6];
+    std::unique_ptr<glm::u8vec4[]> m_pick_data[6];
     static glm::vec3 m_plane_origin[6];
     static glm::vec3 m_plane_normal[6];
     static glm::vec3 m_plane_tangent[6];
@@ -104,6 +106,9 @@ public:
     void stroke_cancel();
     void stroke_commit();
     void clear(const glm::vec4& color = { 1, 1, 1, 0 });
+    void pick_start();
+    void pick_update(int plane);
+    glm::vec4 pick_get(glm::vec2 canvas_loc);
     void snapshot_save(std::string data_path);
     void snapshot_restore();
     void snap_history(const std::vector<int>& planes);
diff --git a/engine/canvas_modes.cpp b/engine/canvas_modes.cpp
index c9654ff..5cff8ad 100644
--- a/engine/canvas_modes.cpp
+++ b/engine/canvas_modes.cpp
@@ -72,9 +72,10 @@ void CanvasModePen::on_MouseEvent(MouseEvent* me, glm::vec2& loc)
     switch (me->m_type)
     {
         case kEventType::MouseDownL:
-            if (App::I.keys[(int)kKey::KeyAlt])
+            if (App::I.keys[(int)kKey::KeyAlt] || m_picking)
             {
                 m_picking = true;
+                canvas->pick_start();
             }
             else
             {
@@ -94,14 +95,46 @@ void CanvasModePen::on_MouseEvent(MouseEvent* me, glm::vec2& loc)
             {
                 m_picking = false;
                 node->mouse_release();
-                int x = me->m_pos.x;
-                int y = App::I.height - me->m_pos.y - 1;
-                float pix[3];
-                glBindFramebuffer(GL_FRAMEBUFFER, 0);
-                glReadPixels(x, y, 1, 1, GL_RGB, GL_FLOAT, pix);
+
+                glm::vec4 pix = canvas->pick_get(loc);
                 auto hsv = convert_rgb2hsv(glm::vec3(pix[0], pix[1], pix[2]));
                 App::I.color->m_hue->set_value(hsv.x);
                 App::I.color->m_quad->set_value(1.f - hsv.y, 1.f - hsv.z);
+                
+                /*
+                glm::vec3 ray_origin;
+                glm::vec3 ray_dir;
+                glm::vec3 hit_pos;
+                glm::vec3 hit_normal;
+                int plane_id;
+                if (canvas->point_trace(loc, ray_origin, ray_dir, hit_pos, hit_normal, plane_id))
+                {
+                    canvas->m_layers[canvas->m_current_layer_idx].m_rtt[plane_id].bindFramebuffer();
+                    glm::vec2 fbpos = (hit_pos.xy() * 0.5f + 0.5f) * glm::vec2(canvas->m_width, canvas->m_height);
+                    int x = fbpos.x;
+                    int y = fbpos.y;
+                    glm::u8vec4 sample;
+                    glReadPixels(x, y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &sample);
+                    glm::vec3 pix = glm::vec3(sample) / 255.f;
+                    auto hsv = convert_rgb2hsv(glm::vec3(pix[0], pix[1], pix[2]));
+                    App::I.color->m_hue->set_value(hsv.x);
+                    App::I.color->m_quad->set_value(1.f - hsv.y, 1.f - hsv.z);
+                    canvas->m_layers[canvas->m_current_layer_idx].m_rtt[plane_id].unbindFramebuffer();
+                }
+                 */
+/*
+                glm::vec2 fbpos = me->m_pos * node->root()->m_zoom;
+                int x = fbpos.x;
+                int y = App::I.height - fbpos.y - 1;
+                glm::i8vec4 sample;
+                glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                glReadBuffer(GL_FRONT);
+                glReadPixels(x, y, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &sample);
+                glm::vec3 pix = glm::vec3(sample) / 255.f;
+                auto hsv = convert_rgb2hsv(glm::vec3(pix[0], pix[1], pix[2]));
+                App::I.color->m_hue->set_value(hsv.x);
+                App::I.color->m_quad->set_value(1.f - hsv.y, 1.f - hsv.z);
+ */
             }
             break;
         case kEventType::MouseMove:
@@ -109,11 +142,7 @@ void CanvasModePen::on_MouseEvent(MouseEvent* me, glm::vec2& loc)
                 canvas->stroke_update(loc, me->m_pressure);
             if (m_picking)
             {
-                int x = me->m_pos.x;
-                int y = App::I.height - me->m_pos.y - 1;
-                float pix[3];
-                glBindFramebuffer(GL_FRAMEBUFFER, 0);
-                glReadPixels(x, y, 1, 1, GL_RGB, GL_FLOAT, pix);
+                glm::vec4 pix = canvas->pick_get(loc);
                 auto hsv = convert_rgb2hsv(glm::vec3(pix[0], pix[1], pix[2]));
                 App::I.color->m_hue->set_value(hsv.x);
                 App::I.color->m_quad->set_value(1.f - hsv.y, 1.f - hsv.z);
diff --git a/engine/canvas_modes.h b/engine/canvas_modes.h
index 886976b..57462dc 100644
--- a/engine/canvas_modes.h
+++ b/engine/canvas_modes.h
@@ -35,13 +35,13 @@ public:
 class CanvasModePen : public CanvasMode
 {
     bool m_dragging = false;
-    bool m_picking = false;
     glm::vec2 m_pan_start;
     float m_camera_fov;
     float m_zoom_canvas = 1.f;
     float m_zoom_start;
 public:
     virtual void on_MouseEvent(MouseEvent* me, glm::vec2& loc) override;
+    bool m_picking = false;
 };
 
 class CanvasModeLine : public CanvasMode
diff --git a/engine/pch.h b/engine/pch.h
index 3219756..0c9f9e1 100644
--- a/engine/pch.h
+++ b/engine/pch.h
@@ -10,6 +10,11 @@
         #define TARGET_OS_IOS 1
         #define __IOS__ 1
         #include <CoreFoundation/CoreFoundation.h>
+        #ifdef __OBJC__
+            #include <Foundation/Foundation.h>
+            #import <UIKit/UIKit.h>
+            #import <GLKit/GLKit.h>
+        #endif
         #include <OpenGLES/ES3/gl.h>
         #include <OpenGLES/ES3/glext.h>
         #define SHADER_VERSION "#version 300 es\n"
@@ -17,6 +22,11 @@
         #define TARGET_OS_IOS 1
         #define __IOS__ 1
         #include <CoreFoundation/CoreFoundation.h>
+        #ifdef __OBJC__
+            #include <Foundation/Foundation.h>
+            #import <UIKit/UIKit.h>
+            #import <GLKit/GLKit.h>
+        #endif
         #include <OpenGLES/ES3/gl.h>
         #include <OpenGLES/ES3/glext.h>
         #define SHADER_VERSION "#version 300 es\n"