From 59dabc7d8dc0f93761412075dd00bec96b0c55e5 Mon Sep 17 00:00:00 2001
From: Jabier Arraiza <jabier.arraiza@marker.es>
Date: Fri, 20 Dec 2019 13:10:18 +0100
Subject: [PATCH] Constrain variable cache limit to zoom or panning

---
 src/display/drawing-item.cpp | 14 +++++++++-----
 src/display/drawing.cpp      |  1 +
 src/display/drawing.h        |  1 +
 src/display/sp-canvas.cpp    | 10 ++++++++++
 4 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/display/drawing-item.cpp b/src/display/drawing-item.cpp
index f7136de6ee..d8d17032d5 100644
--- a/src/display/drawing-item.cpp
+++ b/src/display/drawing-item.cpp
@@ -331,11 +331,15 @@ DrawingItem::setStyle(SPStyle *style, SPStyle *context_style)
     }
 
     if (style && style->enable_background.set) {
-        if (style->enable_background.value == SP_CSS_BACKGROUND_NEW && !_background_new) {
+        bool update = false;
+        if (style->enable_background.value == SP_CSS_BACKGROUND_NEW) {
+            update = _background_new == false;
             _background_new = true;
-            _markForUpdate(STATE_BACKGROUND, true);
-        } else if (style->enable_background.value == SP_CSS_BACKGROUND_ACCUMULATE && _background_new) {
+        } else if (style->enable_background.value == SP_CSS_BACKGROUND_ACCUMULATE) {
+            update = _background_new == true;
             _background_new = false;
+        }
+        if (update) {
             _markForUpdate(STATE_BACKGROUND, true);
         }
     }
@@ -731,7 +735,7 @@ DrawingItem::render(DrawingContext &dc, Geom::IntRect const &area, unsigned flag
             _cache->paintFromCache(dc, carea, _filter && render_filters);
             if (!carea) {
                 dc.setSource(0, 0, 0, 0);
-                return RENDER_OK;
+                return RENDER_OK;       
             }
         } else {
             // There is no cache. This could be because caching of this item
@@ -1185,7 +1189,7 @@ inline void expandByScale(Geom::IntRect &rect, double scale)
 Geom::OptIntRect DrawingItem::_cacheRect(bool cropped)
 {
     Geom::OptIntRect r = _drawbox & _drawing.cacheLimit();
-    if (_filter && _drawing.renderFilters() && r && r != _drawbox) {
+    if (!_drawing.lookCacheLimit && _filter && _drawing.renderFilters() && r && r != _drawbox) {
         // we check unfiltered item is emought inside the cache area to  render properly
         Geom::OptIntRect canvas = r;
         expandByScale(*canvas, 0.5);
diff --git a/src/display/drawing.cpp b/src/display/drawing.cpp
index 4ff7464a21..2eced9f590 100644
--- a/src/display/drawing.cpp
+++ b/src/display/drawing.cpp
@@ -35,6 +35,7 @@ Drawing::Drawing(SPCanvasArena *arena)
     : _root(nullptr)
     , outlinecolor(0x000000ff)
     , delta(0)
+    , lookCacheLimit(true)
     , _exact(false)
     , _outline_sensitive(true)
     , _rendermode(RENDERMODE_NORMAL)
diff --git a/src/display/drawing.h b/src/display/drawing.h
index fb82cdd796..f4e3a84109 100644
--- a/src/display/drawing.h
+++ b/src/display/drawing.h
@@ -92,6 +92,7 @@ public:
     // TODO: remove these temporarily public members
     guint32 outlinecolor;
     double delta;
+    bool lookCacheLimit;
 private:
     bool _exact;  // if true then rendering must be exact
     RenderMode _rendermode;
diff --git a/src/display/sp-canvas.cpp b/src/display/sp-canvas.cpp
index 03e4de86e1..753852eea2 100644
--- a/src/display/sp-canvas.cpp
+++ b/src/display/sp-canvas.cpp
@@ -2580,6 +2580,7 @@ gint SPCanvas::idle_handler(gpointer data)
         SPDesktop *desktop = SP_ACTIVE_DESKTOP;
         if (desktop) {
             SPCanvasArena *arena = SP_CANVAS_ARENA(desktop->drawing);
+            arena->drawing.lookCacheLimit = true;
             Inkscape::RenderMode rm = arena->drawing.renderMode();
             if (rm == Inkscape::RENDERMODE_OUTLINE) {
                 canvas->_totalelapsed = 0;
@@ -2602,6 +2603,11 @@ gint SPCanvas::idle_handler(gpointer data)
         // Reset idle id
         canvas->_idle_id = 0;
         canvas->_scrooling = false;
+        SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+        if (desktop) {
+            SPCanvasArena *arena = SP_CANVAS_ARENA(desktop->drawing);
+            arena->drawing.lookCacheLimit = true;
+        }
     }
 #endif
     return !ret;
@@ -2670,6 +2676,10 @@ void SPCanvas::scrollTo( Geom::Point const &c, unsigned int clear, bool is_scrol
     if (desktop && desktop->splitMode()) {
         split = true;
     }
+    if (desktop) {
+        SPCanvasArena *arena = SP_CANVAS_ARENA(desktop->drawing);
+        arena->drawing.lookCacheLimit = false;
+    }
     if (clear || split || _xray || outsidescrool) {
         _dx0 = cx; // here the 'd' stands for double, not delta!
         _dy0 = cy;
-- 
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