Cleanup: rename USER_ZOOM_{CONT->CONTINUE} improve comments

USER_ZOOM_CONT only had comments saying this was 'oldstyle',
remove these comments, add brief explanations of the zoom style
in the enum.

source/blender/editors/interface/view2d_ops.c

@@ -46,7 +46,7 @@
 #include "UI_interface.h"
 #include "UI_view2d.h"
 
-#include "PIL_time.h" /* USER_ZOOM_CONT */
+#include "PIL_time.h" /* USER_ZOOM_CONTINUE */
 
 /* -------------------------------------------------------------------- */
 /** \name Internal Utilities
@@ -1108,7 +1108,7 @@ static void view_zoomdrag_apply(bContext *C, wmOperator *op)
 
   /* Check if the 'timer' is initialized, as zooming with the trackpad
    * never uses the "Continuous" zoom method, and the 'timer' is not initialized. */
-  if ((U.viewzoom == USER_ZOOM_CONT) && vzd->timer) { /* XXX store this setting as RNA prop? */
+  if ((U.viewzoom == USER_ZOOM_CONTINUE) && vzd->timer) { /* XXX store this setting as RNA prop? */
     const double time = PIL_check_seconds_timer();
     const float time_step = (float)(time - vzd->timer_lastdraw);
 
@@ -1304,7 +1304,7 @@ static int view_zoomdrag_invoke(bContext *C, wmOperator *op, const wmEvent *even
   /* add temp handler */
   WM_event_add_modal_handler(C, op);
 
-  if (U.viewzoom == USER_ZOOM_CONT) {
+  if (U.viewzoom == USER_ZOOM_CONTINUE) {
     /* needs a timer to continue redrawing */
     vzd->timer = WM_event_add_timer(CTX_wm_manager(C), window, TIMER, 0.01f);
     vzd->timer_lastdraw = PIL_check_seconds_timer();
@@ -1363,7 +1363,7 @@ static int view_zoomdrag_modal(bContext *C, wmOperator *op, const wmEvent *event
       dx *= BLI_rctf_size_x(&v2d->cur);
       dy *= BLI_rctf_size_y(&v2d->cur);
     }
-    else { /* USER_ZOOM_CONT or USER_ZOOM_DOLLY */
+    else { /* USER_ZOOM_CONTINUE or USER_ZOOM_DOLLY */
       float facx = zoomfac * (event->x - vzd->lastx);
       float facy = zoomfac * (event->y - vzd->lasty);
 
@@ -1410,7 +1410,7 @@ static int view_zoomdrag_modal(bContext *C, wmOperator *op, const wmEvent *event
      * - Continuous zoom only depends on distance of mouse
      *   to starting point to determine rate of change.
      */
-    if (U.viewzoom != USER_ZOOM_CONT) { /* XXX store this setting as RNA prop? */
+    if (U.viewzoom != USER_ZOOM_CONTINUE) { /* XXX store this setting as RNA prop? */
       vzd->lastx = event->x;
       vzd->lasty = event->y;
     }

source/blender/editors/space_clip/clip_ops.c

@@ -569,7 +569,7 @@ static void view_zoom_init(bContext *C, wmOperator *op, const wmEvent *event)
     WM_cursor_modal_set(win, WM_CURSOR_NSEW_SCROLL);
   }
 
-  if (U.viewzoom == USER_ZOOM_CONT) {
+  if (U.viewzoom == USER_ZOOM_CONTINUE) {
     /* needs a timer to continue redrawing */
     vpd->timer = WM_event_add_timer(CTX_wm_manager(C), CTX_wm_window(C), TIMER, 0.01f);
     vpd->timer_lastdraw = PIL_check_seconds_timer();
@@ -662,7 +662,7 @@ static void view_zoom_apply(
     delta = -delta;
   }
 
-  if (U.viewzoom == USER_ZOOM_CONT) {
+  if (U.viewzoom == USER_ZOOM_CONTINUE) {
     SpaceClip *sclip = CTX_wm_space_clip(C);
     double time = PIL_check_seconds_timer();
     float time_step = (float)(time - vpd->timer_lastdraw);

source/blender/editors/space_image/image_ops.c

@@ -467,7 +467,7 @@ static void image_view_zoom_init(bContext *C, wmOperator *op, const wmEvent *eve
   UI_view2d_region_to_view(
       &region->v2d, event->mval[0], event->mval[1], &vpd->location[0], &vpd->location[1]);
 
-  if (U.viewzoom == USER_ZOOM_CONT) {
+  if (U.viewzoom == USER_ZOOM_CONTINUE) {
     /* needs a timer to continue redrawing */
     vpd->timer = WM_event_add_timer(CTX_wm_manager(C), CTX_wm_window(C), TIMER, 0.01f);
     vpd->timer_lastdraw = PIL_check_seconds_timer();
@@ -579,12 +579,10 @@ static void image_zoom_apply(ViewZoomData *vpd,
     delta = -delta;
   }
 
-  if (viewzoom == USER_ZOOM_CONT) {
+  if (viewzoom == USER_ZOOM_CONTINUE) {
     double time = PIL_check_seconds_timer();
     float time_step = (float)(time - vpd->timer_lastdraw);
     float zfac;
-
-    /* oldstyle zoom */
     zfac = 1.0f + ((delta / 20.0f) * time_step);
     vpd->timer_lastdraw = time;
     /* this is the final zoom, but instead make it into a factor */

source/blender/editors/space_view3d/view3d_edit.c

@@ -2025,7 +2025,7 @@ static float viewzoom_scale_value(const rcti *winrct,
 {
   float zfac;
 
-  if (viewzoom == USER_ZOOM_CONT) {
+  if (viewzoom == USER_ZOOM_CONTINUE) {
     double time = PIL_check_seconds_timer();
     float time_step = (float)(time - *r_timer_lastdraw);
     float fac;
@@ -2043,7 +2043,6 @@ static float viewzoom_scale_value(const rcti *winrct,
       fac = -fac;
     }
 
-    /* oldstyle zoom */
     zfac = 1.0f + ((fac / 20.0f) * time_step);
     *r_timer_lastdraw = time;
   }
@@ -2405,7 +2404,7 @@ static int viewzoom_invoke(bContext *C, wmOperator *op, const wmEvent *event)
       return OPERATOR_FINISHED;
     }
 
-    if (U.viewzoom == USER_ZOOM_CONT) {
+    if (U.viewzoom == USER_ZOOM_CONTINUE) {
       /* needs a timer to continue redrawing */
       vod->timer = WM_event_add_timer(CTX_wm_manager(C), CTX_wm_window(C), TIMER, 0.01f);
       vod->prev.time = PIL_check_seconds_timer();

source/blender/makesdna/DNA_userdef_types.h

@@ -1013,8 +1013,11 @@ typedef enum ePathCompare_Flag {
 
 /** #UserDef.viewzoom */
 typedef enum eViewZoom_Style {
-  USER_ZOOM_CONT = 0,
+  /** Update zoom continuously with a timer while dragging the cursor. */
+  USER_ZOOM_CONTINUE = 0,
+  /** Map changes in distance from the view center to zoom. */
   USER_ZOOM_SCALE = 1,
+  /** Map horizontal/vertical motion to zoom. */
   USER_ZOOM_DOLLY = 2,
 } eViewZoom_Style;
 

source/blender/makesrna/intern/rna_userdef.c

@@ -5654,7 +5654,7 @@ static void rna_def_userdef_input(BlenderRNA *brna)
   };
 
   static const EnumPropertyItem view_zoom_styles[] = {
-      {USER_ZOOM_CONT,
+      {USER_ZOOM_CONTINUE,
        "CONTINUE",
        0,
        "Continue",