Zoom to frame options, requested by the Hwoozeberry (dutch translation)

team.

There are 3 options here:

1) Keep range (previous behaviour)
2) Seconds - allows a specified offset in seconds around current frame
3) keyframes - zoom to include a number of keyframes around the cursor

Options 2 and 3 have their own properties to tweak the behaviour and all
options can be found in User Preferences->Interface under the 2D
viewports section.

Number 3 will probably need some refinement so commiting here for the
hwoozeberry team to test first.

release/scripts/startup/bl_ui/space_userpref.py

@@ -200,6 +200,11 @@ class USERPREF_PT_interface(Panel):
         col.label(text="2D Viewports:")
         col.prop(view, "view2d_grid_spacing_min", text="Minimum Grid Spacing")
         col.prop(view, "timecode_style")
+        col.prop(view, "view_frame_type")
+        if (view.view_frame_type == 'SECONDS'):
+            col.prop(view, "view_frame_seconds")
+        elif (view.view_frame_type == 'KEYFRAMES'):
+            col.prop(view, "view_frame_keyframes")
 
         row.separator()
         row.separator()

source/blender/editors/animation/anim_draw.c

@@ -34,17 +34,25 @@
 #include "DNA_scene_types.h"
 #include "DNA_space_types.h"
 #include "DNA_userdef_types.h"
+#include "DNA_screen_types.h"
+#include "DNA_object_types.h"
+#include "DNA_gpencil_types.h"
+#include "DNA_mask_types.h"
 
 #include "BLI_math.h"
 #include "BLI_timecode.h"
 #include "BLI_utildefines.h"
+#include "BLI_rect.h"
+#include "BLI_dlrbTree.h"
 
 #include "BKE_context.h"
 #include "BKE_global.h"
 #include "BKE_nla.h"
+#include "BKE_mask.h"
 
 #include "ED_anim_api.h"
 #include "ED_keyframes_edit.h"
+#include "ED_keyframes_draw.h"
 
 #include "RNA_access.h"
 
@@ -381,4 +389,136 @@ float ANIM_unit_mapping_get_factor(Scene *scene, ID *id, FCurve *fcu, short flag
 	return 1.0f;
 }
 
+static bool find_prev_next_keyframes(struct bContext *C, int *nextfra, int *prevfra) {
+	Scene *scene = CTX_data_scene(C);
+	Object *ob = CTX_data_active_object(C);
+	bGPdata *gpd = CTX_data_gpencil_data(C);
+	Mask *mask = CTX_data_edit_mask(C);
+	bDopeSheet ads = {NULL};
+	DLRBT_Tree keys;
+	ActKeyColumn *aknext, *akprev;
+	float cfranext, cfraprev;
+	bool donenext = false, doneprev = false;
+	int nextcount = 0, prevcount = 0;
+
+	cfranext = cfraprev = (float)(CFRA);
+
+	/* init binarytree-list for getting keyframes */
+	BLI_dlrbTree_init(&keys);
+
+	/* seed up dummy dopesheet context with flags to perform necessary filtering */
+	if ((scene->flag & SCE_KEYS_NO_SELONLY) == 0) {
+		/* only selected channels are included */
+		ads.filterflag |= ADS_FILTER_ONLYSEL;
+	}
+
+	/* populate tree with keyframe nodes */
+	scene_to_keylist(&ads, scene, &keys, NULL);
+
+	if (ob)
+		ob_to_keylist(&ads, ob, &keys, NULL);
+
+	gpencil_to_keylist(&ads, gpd, &keys);
+
+	if (mask) {
+		MaskLayer *masklay = BKE_mask_layer_active(mask);
+		mask_to_keylist(&ads, masklay, &keys);
+	}
+
+	/* build linked-list for searching */
+	BLI_dlrbTree_linkedlist_sync(&keys);
+
+	/* find matching keyframe in the right direction */
+	do {
+		aknext = (ActKeyColumn *)BLI_dlrbTree_search_next(&keys, compare_ak_cfraPtr, &cfranext);
+
+		if (aknext) {
+			if (CFRA == (int)aknext->cfra) {
+				/* make this the new starting point for the search and ignore */
+				cfranext = aknext->cfra;
+			}
+			else {
+				/* this changes the frame, so set the frame and we're done */
+				if (++nextcount == U.view_frame_keyframes)
+					donenext = true;
+			}
+			cfranext = aknext->cfra;
+		}
+	} while ((aknext != NULL) && (donenext == false));
+
+	do {
+		akprev = (ActKeyColumn *)BLI_dlrbTree_search_prev(&keys, compare_ak_cfraPtr, &cfraprev);
+
+		if (akprev) {
+			if (CFRA == (int)akprev->cfra) {
+				/* make this the new starting point for the search */
+			}
+			else {
+				/* this changes the frame, so set the frame and we're done */
+				if (++prevcount == U.view_frame_keyframes)
+					doneprev = true;
+			}
+			cfraprev = akprev->cfra;
+		}
+	} while ((akprev != NULL) && (doneprev == false));
+
+	/* free temp stuff */
+	BLI_dlrbTree_free(&keys);
+
+	/* any success? */
+	if (doneprev || donenext) {
+		if (doneprev)
+			*prevfra = cfraprev;
+		else
+			*prevfra = CFRA - (cfranext - CFRA);
+
+		if (donenext)
+			*nextfra = cfranext;
+		else
+			*nextfra = CFRA + (CFRA - cfraprev);
+
+		return true;
+	}
+
+	return false;
+}
+
+void ANIM_center_frame(struct bContext *C, int smooth_viewtx)
+{
+	ARegion *ar = CTX_wm_region(C);
+	Scene *scene = CTX_data_scene(C);
+	float w = BLI_rctf_size_x(&ar->v2d.cur);
+	rctf newrct;
+	int nextfra, prevfra;
+
+	switch (U.view_frame_type) {
+		case ZOOM_FRAME_MODE_SECONDS:
+			newrct.xmax = scene->r.cfra + U.view_frame_seconds * FPS + 1;
+			newrct.xmin = scene->r.cfra - U.view_frame_seconds * FPS - 1;
+			newrct.ymax = ar->v2d.cur.ymax;
+			newrct.ymin = ar->v2d.cur.ymin;
+			break;
+
+		/* hardest case of all, look for all keyframes around frame and display those */
+		case ZOOM_FRAME_MODE_KEYFRAMES:
+			if (find_prev_next_keyframes(C, &nextfra, &prevfra)) {
+				newrct.xmax = nextfra;
+				newrct.xmin = prevfra;
+				newrct.ymax = ar->v2d.cur.ymax;
+				newrct.ymin = ar->v2d.cur.ymin;
+				break;
+			}
+			/* else drop through, keep range instead */
+
+		case ZOOM_FRAME_MODE_KEEP_RANGE:
+		default:
+			newrct.xmax = scene->r.cfra + (w / 2);
+			newrct.xmin = scene->r.cfra - (w / 2);
+			newrct.ymax = ar->v2d.cur.ymax;
+			newrct.ymin = ar->v2d.cur.ymin;
+			break;
+	}
+
+	UI_view2d_smooth_view(C, ar, &newrct, smooth_viewtx);
+}
 /* *************************************************** */

source/blender/editors/include/ED_anim_api.h

@@ -659,6 +659,7 @@ void ANIM_list_elem_update(struct Scene *scene, bAnimListElem *ale);
 /* data -> channels syncing */
 void ANIM_sync_animchannels_to_data(const struct bContext *C);
 
+void ANIM_center_frame(struct bContext *C, int smooth_viewtx);
 /* ************************************************* */
 /* OPERATORS */
 	

source/blender/editors/include/UI_view2d.h

@@ -233,7 +233,6 @@ void ED_keymap_view2d(struct wmKeyConfig *keyconf);
 
 void UI_view2d_smooth_view(struct bContext *C, struct ARegion *ar,
                            const struct rctf *cur, const int smooth_viewtx);
-void UI_view2d_center_frame(struct bContext *C, int smooth_viewtx);
 #define UI_MARKER_MARGIN_Y (42 * UI_DPI_FAC)
 
 #endif /* __UI_VIEW2D_H__ */

source/blender/editors/interface/view2d_ops.c

@@ -1468,21 +1468,6 @@ void UI_view2d_smooth_view(
 	}
 }
 
-void UI_view2d_center_frame(struct bContext *C, int smooth_viewtx)
-{
-	ARegion *ar = CTX_wm_region(C);
-	Scene *scene = CTX_data_scene(C);
-	float w = BLI_rctf_size_x(&ar->v2d.cur);
-	rctf newrct;
-
-	newrct.xmax = scene->r.cfra + (w / 2);
-	newrct.xmin = scene->r.cfra - (w / 2);
-	newrct.ymax = ar->v2d.cur.ymax;
-	newrct.ymin = ar->v2d.cur.ymin;
-
-	UI_view2d_smooth_view(C, ar, &newrct, smooth_viewtx);
-}
-
 /* only meant for timer usage */
 static int view2d_smoothview_invoke(bContext *C, wmOperator *UNUSED(op), const wmEvent *event)
 {

source/blender/editors/space_action/action_edit.c

@@ -429,7 +429,7 @@ static int actkeys_viewsel_exec(bContext *C, wmOperator *UNUSED(op))
 static int actkeys_view_frame_exec(bContext *C, wmOperator *op)
 {
 	const int smooth_viewtx = WM_operator_smooth_viewtx_get(op);
-	UI_view2d_center_frame(C, smooth_viewtx);
+	ANIM_center_frame(C, smooth_viewtx);
 
 	return OPERATOR_FINISHED;
 }

source/blender/editors/space_graph/graph_edit.c

@@ -261,7 +261,7 @@ static int graphkeys_view_selected_exec(bContext *C, wmOperator *op)
 static int graphkeys_view_frame_exec(bContext *C, wmOperator *op)
 {
 	const int smooth_viewtx = WM_operator_smooth_viewtx_get(op);
-	UI_view2d_center_frame(C, smooth_viewtx);
+	ANIM_center_frame(C, smooth_viewtx);
 	return OPERATOR_FINISHED;
 }
 

source/blender/makesdna/DNA_userdef_types.h

@@ -503,7 +503,10 @@ typedef struct UserDef {
 	char  ipo_new;			/* interpolation mode for newly added F-Curves */
 	char  keyhandles_new;	/* handle types for newly added keyframes */
 	char  gpu_select_method;
-	char  pad1;
+	char  view_frame_type;
+
+	int view_frame_keyframes; /* number of keyframes to zoom around current frame */
+	float view_frame_seconds; /* seconds to zoom around current frame */
 
 	short scrcastfps;		/* frame rate for screencast to be played back */
 	short scrcastwait;		/* milliseconds between screencast snapshots */
@@ -686,6 +689,13 @@ typedef enum eAutokey_Mode {
 	AUTOKEY_MODE_EDITKEYS  = 5
 } eAutokey_Mode;
 
+/* Zoom to frame mode */
+typedef enum eZoomFrame_Mode {
+	ZOOM_FRAME_MODE_KEEP_RANGE = 0,
+	ZOOM_FRAME_MODE_SECONDS = 1,
+	ZOOM_FRAME_MODE_KEYFRAMES = 2
+} eZoomFrame_Mode;
+
 /* Auto-Keying flag
  * U.autokey_flag (not strictly used when autokeying only - is also used when keyframing these days)
  * note: AUTOKEY_FLAG_* is used with a macro, search for lines like IS_AUTOKEY_FLAG(INSERTAVAIL)

source/blender/makesrna/intern/rna_userdef.c

@@ -3264,6 +3264,13 @@ static void rna_def_userdef_view(BlenderRNA *brna)
 		{0, NULL, 0, NULL, NULL}
 	};
 
+	static EnumPropertyItem zoom_frame_modes[] = {
+		{ZOOM_FRAME_MODE_KEEP_RANGE, "KEEP_RANGE", 0, "Keep Range", ""},
+		{ZOOM_FRAME_MODE_SECONDS, "SECONDS", 0, "Seconds", ""},
+	    {ZOOM_FRAME_MODE_KEYFRAMES, "KEYFRAMES", 0, "Keyframes", ""},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	PropertyRNA *prop;
 	StructRNA *srna;
 	
@@ -3505,6 +3512,22 @@ static void rna_def_userdef_view(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "TimeCode Style",
 	                         "Format of Time Codes displayed when not displaying timing in terms of frames");
 	RNA_def_property_update(prop, 0, "rna_userdef_update");
+
+	prop = RNA_def_property(srna, "view_frame_type", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(prop, zoom_frame_modes);
+	RNA_def_property_enum_sdna(prop, NULL, "view_frame_type");
+	RNA_def_property_ui_text(prop, "Zoom To Frame Type", "How zooming to frame focuses around current frame");
+
+	prop = RNA_def_property(srna, "view_frame_keyframes", PROP_INT, PROP_NONE);
+	RNA_def_property_range(prop, 1, 500);
+	RNA_def_property_ui_text(prop, "Zoom Keyframes",
+	                         "Keyframes around cursor that we zoom around");
+
+	prop = RNA_def_property(srna, "view_frame_seconds", PROP_FLOAT, PROP_TIME);
+	RNA_def_property_range(prop, 0.0, 10000.0);
+	RNA_def_property_ui_text(prop, "Zoom Seconds",
+	                         "Seconds around cursor that we zoom around");
+
 }
 
 static void rna_def_userdef_edit(BlenderRNA *brna)