Merge pull request #242 from jpirnay/refactor-pr

perf: Shrink HomeActivity cover cache from 48KB framebuffer to 16KB region (PR 2035 by jeremydk)

src/activities/home/HomeActivity.cpp

@@ -384,37 +384,28 @@ void HomeActivity::onExit() {
 }
 
 bool HomeActivity::storeCoverBuffer() {
-  uint8_t* frameBuffer = renderer.getFrameBuffer();
-  if (!frameBuffer) {
-    return false;
-  }
-
-  // Free any existing buffer first
+  if (coverRectW <= 0 || coverRectH <= 0) return false;
   freeCoverBuffer();
-
-  const size_t bufferSize = renderer.getBufferSize();
-  coverBuffer = static_cast<uint8_t*>(malloc(bufferSize));
+  const size_t needed = renderer.getRegionByteSize(coverRectX, coverRectY, coverRectW, coverRectH);
+  if (needed == 0) return false;
+  coverBuffer = static_cast<uint8_t*>(malloc(needed));
   if (!coverBuffer) {
+    LOG_ERR("HOME", "OOM: cover buffer (%u bytes)", (unsigned)needed);
+    return false;
+  }
+  coverBufferSize = needed;
+  if (!renderer.copyRegionToBuffer(coverRectX, coverRectY, coverRectW, coverRectH, coverBuffer, coverBufferSize)) {
+    free(coverBuffer);
+    coverBuffer = nullptr;
+    coverBufferSize = 0;
     return false;
   }
-
-  memcpy(coverBuffer, frameBuffer, bufferSize);
   return true;
 }
 
 bool HomeActivity::restoreCoverBuffer() {
-  if (!coverBuffer) {
-    return false;
-  }
-
-  uint8_t* frameBuffer = renderer.getFrameBuffer();
-  if (!frameBuffer) {
-    return false;
-  }
-
-  const size_t bufferSize = renderer.getBufferSize();
-  memcpy(frameBuffer, coverBuffer, bufferSize);
-  return true;
+  if (!coverBuffer || coverRectW <= 0 || coverRectH <= 0) return false;
+  return renderer.copyBufferToRegion(coverRectX, coverRectY, coverRectW, coverRectH, coverBuffer, coverBufferSize);
 }
 
 void HomeActivity::freeCoverBuffer() {
@@ -422,6 +413,7 @@ void HomeActivity::freeCoverBuffer() {
     free(coverBuffer);
     coverBuffer = nullptr;
   }
+  coverBufferSize = 0;
   coverBufferStored = false;
 }
 
@@ -549,6 +541,11 @@ void HomeActivity::render(RenderLock&&) {
 
   const HomeScreenLayout layout = computeHomeScreenLayout(metrics, contentRect.height, menuCount);
 
+  coverRectX = contentRect.x;
+  coverRectY = metrics.homeTopPadding;
+  coverRectW = contentRect.width;
+  coverRectH = layout.recentTileHeight;
+
   GUI.drawRecentBookCover(renderer,
                           Rect{contentRect.x, metrics.homeTopPadding, contentRect.width, layout.recentTileHeight},
                           recentBooks, selectorIndex, coverRendered, coverBufferStored, bufferRestored,

src/activities/home/HomeActivity.h

@@ -41,6 +41,11 @@ class HomeActivity final : public Activity {
   bool coverBufferStored = false;
   size_t nextRecentCoverIndex = 0;
   uint8_t* coverBuffer = nullptr;
+  size_t coverBufferSize = 0;
+  int coverRectX = 0;
+  int coverRectY = 0;
+  int coverRectW = 0;
+  int coverRectH = 0;
 
   std::vector<RecentBook> recentBooks;
   std::vector<MenuEntry> menuEntries;