diff --git a/CMakeLists.txt b/CMakeLists.txt
index 92d30e0..f190c75 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -293,6 +293,8 @@ set(VMIX_RSC_FILES
     ./rsc/shaders/mask_elipse.fs
     ./rsc/shaders/mask_box.fs
     ./rsc/shaders/mask_round.fs
+    ./rsc/shaders/mask_lowleftcorner.fs
+    ./rsc/shaders/mask_uprightcorner.fs
     ./rsc/shaders/image.vs
     ./rsc/shaders/imageprocessing.fs
     ./rsc/fonts/Hack-Regular.ttf
diff --git a/ImageShader.cpp b/ImageShader.cpp
index 2539894..5443ab0 100644
--- a/ImageShader.cpp
+++ b/ImageShader.cpp
@@ -9,7 +9,12 @@
 
 static ShadingProgram imageShadingProgram("shaders/image.vs", "shaders/image.fs");
 
-const char* MaskShader::mask_names[4] = { ICON_FA_EXPAND, ICON_FA_CIRCLE, ICON_FA_MINUS_CIRCLE, ICON_FA_SQUARE };
+const char* MaskShader::mask_names[6] = { ICON_FA_EXPAND,
+                                          ICON_FA_CIRCLE,
+                                          ICON_FA_MINUS_CIRCLE,
+                                          ICON_FA_SQUARE,
+                                          ICON_FA_CARET_SQUARE_RIGHT,
+                                          ICON_FA_CARET_SQUARE_LEFT };
 std::vector< ShadingProgram* > MaskShader::mask_programs;
 
 ImageShader::ImageShader(): Shader(), stipple(0.0)
@@ -70,6 +75,8 @@ MaskShader::MaskShader(): Shader(), mode(0)
         mask_programs.push_back(new ShadingProgram("shaders/simple.vs", "shaders/mask_elipse.fs"));
         mask_programs.push_back(new ShadingProgram("shaders/simple.vs", "shaders/mask_round.fs"));
         mask_programs.push_back(new ShadingProgram("shaders/simple.vs", "shaders/mask_box.fs"));
+        mask_programs.push_back(new ShadingProgram("shaders/simple.vs", "shaders/mask_lowleftcorner.fs"));
+        mask_programs.push_back(new ShadingProgram("shaders/simple.vs", "shaders/mask_uprightcorner.fs"));
     }
     // reset instance
     reset();
diff --git a/ImageShader.h b/ImageShader.h
index 795cc05..5aead30 100644
--- a/ImageShader.h
+++ b/ImageShader.h
@@ -1,4 +1,4 @@
-#ifndef IMAGESHADER_H
+#ifndef IMAGESHADER_H
 #define IMAGESHADER_H
 
 #include <string>
@@ -47,7 +47,7 @@ public:
     float blur;
     glm::vec2 size;
 
-    static const char* mask_names[4];
+    static const char* mask_names[6];
     static std::vector< ShadingProgram* > mask_programs;
 };
 
diff --git a/View.cpp b/View.cpp
index 32c2435..24e088f 100644
--- a/View.cpp
+++ b/View.cpp
@@ -1881,8 +1881,9 @@ AppearanceView::AppearanceView() : View(APPEARANCE), edit_source_(nullptr), need
     // marks on the frame to show scale
     show_scale_ = false;
     horizontal_mark_ = new Mesh("mesh/h_mark.ply");
-    horizontal_mark_->translation_ = glm::vec3(0.f, 1.f, 0.0f);
+    horizontal_mark_->translation_ = glm::vec3(0.f, -1.f, 0.0f);
     horizontal_mark_->scale_ = glm::vec3(2.5f, -2.5f, 0.0f);
+    horizontal_mark_->rotation_.z = M_PI;
     horizontal_mark_->shader()->color = glm::vec4( COLOR_TRANSITION_LINES, 0.9f );
     scene.bg()->attach(horizontal_mark_);
     vertical_mark_  = new Mesh("mesh/h_mark.ply");
@@ -2146,7 +2147,14 @@ void AppearanceView::adjustBackground()
         mask_node_->visible_ = edit_source_->maskShader()->mode > 0;
         mask_circle_->visible_ = edit_source_->maskShader()->mode == 1;
         mask_square_->visible_ = edit_source_->maskShader()->mode >= 2;
-        mask_node_->scale_ = scale * glm::vec3(edit_source_->maskShader()->size, 1.f);
+        if (edit_source_->maskShader()->mode >= 4) {
+            mask_node_->scale_ = scale;
+            mask_node_->translation_ = scale - glm::vec3(edit_source_->maskShader()->size, 0.f) * scale ;
+            mask_node_->translation_.z = 0.f;
+        } else {
+            mask_node_->scale_ = scale * glm::vec3(edit_source_->maskShader()->size, 1.f);
+            mask_node_->translation_ = glm::vec3(0.f);
+        }
         mask_corner_->scale_.y = mask_corner_->scale_.x * mask_node_->scale_.x / mask_node_->scale_.y;
     }
 
diff --git a/rsc/shaders/mask_lowleftcorner.fs b/rsc/shaders/mask_lowleftcorner.fs
new file mode 100644
index 0000000..ea17752
--- /dev/null
+++ b/rsc/shaders/mask_lowleftcorner.fs
@@ -0,0 +1,36 @@
+#version 330 core
+
+out vec4 FragColor;
+
+in vec4 vertexColor;
+in vec2 vertexUV;
+
+// from General Shader
+uniform vec3 iResolution;      // viewport resolution (in pixels)
+uniform mat4 iTransform;       // image transformation
+uniform vec4 color;            // drawing color
+uniform vec4 uv;
+
+// Mask Shader
+uniform vec2 size;
+uniform float blur;
+
+float sdRoundSide( in vec2 p, in vec2 b, in float r )
+{
+    vec2 q = vec2(-1.0, 1.0) * p - b + r;
+    return min(max(q.x,q.y),0.0) + length(max(q,0.0)) - r;
+}
+
+void main()
+{
+    vec2 uv = -1.0 + 2.0 * gl_FragCoord.xy / iResolution.xy;
+    uv.x *= iResolution.x / iResolution.y;
+
+    float d = sdRoundSide( uv, vec2(size.x * iResolution.x/iResolution.y, size.y), blur );
+
+    vec3 col = vec3(1.0 - sign(d));
+    float delta = 0.5 * length(min(size,1.0));
+    col *= 1.0 - exp( -30.0/ (blur * 100.0 * delta + 1.0) * abs(d));
+
+    FragColor = vec4( col, 1.0 );
+}
diff --git a/rsc/shaders/mask_uprightcorner.fs b/rsc/shaders/mask_uprightcorner.fs
new file mode 100644
index 0000000..72a7081
--- /dev/null
+++ b/rsc/shaders/mask_uprightcorner.fs
@@ -0,0 +1,38 @@
+#version 330 core
+
+out vec4 FragColor;
+
+in vec4 vertexColor;
+in vec2 vertexUV;
+
+// from General Shader
+uniform vec3 iResolution;      // viewport resolution (in pixels)
+uniform mat4 iTransform;       // image transformation
+uniform vec4 color;            // drawing color
+uniform vec4 uv;
+
+// Mask Shader
+uniform vec2 size;
+uniform float blur;
+
+
+float sdRoundSide( in vec2 p, in vec2 b, in float r )
+{
+    vec2 q = vec2(1.0, -1.0) * p - b + r;
+    return min(max(q.x,q.y),0.0) + length(max(q,0.0)) - r;
+}
+
+void main()
+{
+    vec2 uv = -1.0 + 2.0 * gl_FragCoord.xy / iResolution.xy;
+    uv.x *= iResolution.x / iResolution.y;
+
+    vec2 s = 2.0 - size;
+    float d = sdRoundSide( uv, vec2(s.x * iResolution.x/iResolution.y, s.y), blur );
+
+    vec3 col = vec3(1.0 - sign(d));
+    float delta = 0.5 * length(min(size,1.0));
+    col *= 1.0 - exp( -20.0/ (blur * 100.0 * delta + 1.0)  * abs(d) );
+
+    FragColor = vec4( col, 1.0 );
+}