Fix viewport resize

Author: jeremyong

lib/Flop.cpp

@@ -835,20 +835,15 @@ int flop_analyze(char const* reference_path,
               << "Error histogram: \n[";
 
 
-    float average_error = 0.f;
     uint32_t histogram[32];
     std::memcpy(histogram, g_error_histogram.data_, sizeof(uint32_t) * 32);
     std::printf("%i", histogram[0]);
     uint32_t sample_count = histogram[0];
     for (uint32_t i = 1; i != 32u; ++i)
     {
         std::printf(", %i", histogram[i]);
-        average_error += histogram[i] * i / 32.f;
-        sample_count += histogram[i];
     }
     std::printf("]\n");
 
-    std::printf("Averaage error: %f\n", average_error);
-
     return 0;
 }

src/Preview.cpp

@@ -154,6 +154,11 @@ void Preview::set_image(Image& image)
 void Preview::set_viewport(Rect2D viewport)
 {
     viewport_ = viewport;
+    if (!image_ || !image_->image_)
+    {
+        viewport_dirty_ = true;
+        return;
+    }
 
     if (image_->aspect() < preview_viewport_.width / preview_viewport_.height)
     {
@@ -261,11 +266,17 @@ float Preview::min_scale() const
 
 void Preview::render(GLFWwindow* window, VkCommandBuffer cb)
 {
-    if (image_ == nullptr || viewport_.x2 == 0)
+    if (image_ == nullptr || image_->image_ == VK_NULL_HANDLE || viewport_.x2 == 0)
     {
         return;
     }
 
+    if (viewport_dirty_)
+    {
+        set_viewport(viewport_);
+        viewport_dirty_ = false;
+    }
+
     if (pan_active_)
     {
         double cx;

src/Preview.hpp

@@ -61,5 +61,6 @@ class Preview
     uint32_t color_map_          = 0;
     bool use_color_map_          = false;
     bool pan_active_             = false;
+    bool viewport_dirty_         = false;
     Quadrant quadrant_           = Quadrant::TopLeft;
 };