Added crop scaling method

Added a method that scales and crop the image so that the image will
fill the whole window.

Also made viewport update respect the current scaling mode.

3 files changed, 62 insertions, 24 deletions

diff --git a/src/imv.c b/src/imv.c
index b12ed98..2c22f24 100644
--- a/src/imv.c
+++ b/src/imv.c
@@ -29,17 +29,11 @@
 #define PATH_MAX 4096
 #endif
 
-enum scaling_mode {
-  SCALING_NONE,
-  SCALING_DOWN,
-  SCALING_FULL,
-  SCALING_MODE_COUNT
-};
-
 static const char *scaling_label[] = {
   "actual size",
   "shrink to fit",
-  "scale to fit"
+  "scale to fit",
+  "crop"
 };
 
 enum background_type {
@@ -435,7 +429,7 @@ static void event_handler(void *data, const struct imv_event *e)
         const int wh = e->data.resize.height;
         const int bw = e->data.resize.buffer_width;
         const int bh = e->data.resize.buffer_height;
-        imv_viewport_update(imv->view, ww, wh, bw, bh, imv->current_image);
+        imv_viewport_update(imv->view, ww, wh, bw, bh, imv->current_image, imv->scaling_mode);
         imv_canvas_resize(imv->canvas, bw, bh);
         break;
       }
@@ -651,6 +645,11 @@ static bool parse_scaling_mode(struct imv *imv, const char *mode)
     return true;
   }
 
+  if (!strcmp(mode, "crop")) {
+    imv->scaling_mode = SCALING_CROP;
+    return true;
+  }
+
   if (!strcmp(mode, "none")) {
     imv->scaling_mode = SCALING_NONE;
     return true;
@@ -960,18 +959,8 @@ int imv_run(struct imv *imv)
     }
 
     if (imv->need_rescale) {
-      int ww, wh;
-      imv_window_get_size(imv->window, &ww, &wh);
-
       imv->need_rescale = false;
-      if (imv->scaling_mode == SCALING_NONE ||
-          (imv->scaling_mode == SCALING_DOWN
-           && ww > imv_image_width(imv->current_image)
-           && wh > imv_image_height(imv->current_image))) {
-        imv_viewport_scale_to_actual(imv->view, imv->current_image);
-      } else {
-        imv_viewport_scale_to_window(imv->view, imv->current_image);
-      }
+      imv_viewport_rescale(imv->view, imv->current_image, imv->scaling_mode);
     }
 
     current_time = cur_time();
diff --git a/src/viewport.c b/src/viewport.c
index ce9fa54..5b8b3c7 100644
--- a/src/viewport.c
+++ b/src/viewport.c
@@ -220,15 +220,48 @@ void imv_viewport_scale_to_window(struct imv_viewport *view, const struct imv_im
   view->locked = 0;
 }
 
+void imv_viewport_crop_to_window(struct imv_viewport *view, const struct imv_image *image)
+{
+  const int image_width = imv_image_width(image);
+  const int image_height = imv_image_height(image);
+  const double window_aspect = (double)view->buffer.width / (double)view->buffer.height;
+  const double image_aspect = (double)image_width / (double)image_height;
+
+  /* Scale the image so that it fills the whole window */
+  if(window_aspect > image_aspect) {
+    view->scale = (double)view->buffer.width / (double)image_width;
+  } else {
+    view->scale = (double)view->buffer.height / (double)image_height;
+  }
+
+  imv_viewport_center(view, image);
+  view->locked = 0;
+}
+
 void imv_viewport_set_redraw(struct imv_viewport *view)
 {
   view->redraw = 1;
 }
 
+void imv_viewport_rescale(struct imv_viewport *view, const struct imv_image *image,
+                          enum scaling_mode scaling_mode) {
+  if (scaling_mode == SCALING_NONE ||
+      (scaling_mode == SCALING_DOWN
+       && view->buffer.width > imv_image_width(image)
+       && view->buffer.height > imv_image_height(image))) {
+    imv_viewport_scale_to_actual(view, image);
+  } else if (scaling_mode == SCALING_CROP) {
+    imv_viewport_crop_to_window(view, image);
+  } else {
+    imv_viewport_scale_to_window(view, image);
+  }
+}
+
 void imv_viewport_update(struct imv_viewport *view,
                          int window_width, int window_height,
                          int buffer_width, int buffer_height,
-                         struct imv_image *image)
+                         struct imv_image *image,
+                         enum scaling_mode scaling_mode)
 {
   view->window.width = window_width;
   view->window.height = window_height;
@@ -241,7 +274,7 @@ void imv_viewport_update(struct imv_viewport *view,
   }
 
   imv_viewport_center(view, image);
-  imv_viewport_scale_to_window(view, image);
+  imv_viewport_rescale(view, image, scaling_mode);
 }
 
 int imv_viewport_needs_redraw(struct imv_viewport *view)
diff --git a/src/viewport.h b/src/viewport.h
index 0b9519f..5e5bc24 100644
--- a/src/viewport.h
+++ b/src/viewport.h
@@ -6,6 +6,14 @@
 
 struct imv_viewport;
 
+enum scaling_mode {
+  SCALING_NONE,
+  SCALING_DOWN,
+  SCALING_FULL,
+  SCALING_CROP,
+  SCALING_MODE_COUNT
+};
+
 /* Used to signify how a a user requested a zoom */
 enum imv_zoom_source {
   IMV_ZOOM_MOUSE,
@@ -55,10 +63,18 @@ void imv_viewport_center(struct imv_viewport *view,
 void imv_viewport_scale_to_actual(struct imv_viewport *view,
                                   const struct imv_image *image);
 
-/* Scale the view so that the image fills the window */
+/* Scale the view so that the image fits in the window */
 void imv_viewport_scale_to_window(struct imv_viewport *view,
                                   const struct imv_image *image);
 
+/* Scale the view so that the image fills the window */
+void imv_viewport_crop_to_window(struct imv_viewport *view,
+                                  const struct imv_image *image);
+
+/* Rescale the view with the chosen scaling method */
+void imv_viewport_rescale(struct imv_viewport *view, const struct imv_image *image,
+                          enum scaling_mode);
+
 /* Tell the viewport that it needs to be redrawn */
 void imv_viewport_set_redraw(struct imv_viewport *view);
 
@@ -66,7 +82,7 @@ void imv_viewport_set_redraw(struct imv_viewport *view);
 void imv_viewport_update(struct imv_viewport *view,
                          int window_width, int window_height,
                          int buffer_width, int buffer_height,
-                         struct imv_image *image);
+                         struct imv_image *image, enum scaling_mode);
 
 /* Poll whether we need to redraw */
 int imv_viewport_needs_redraw(struct imv_viewport *view);