From 687f70ceca88324fb8f376e086a55b341dd34e6f Mon Sep 17 00:00:00 2001
From: Campbell Barton <ideasman42@gmail.com>
Date: Mon, 6 Sep 2021 20:04:26 +1000
Subject: ImBuf: add IMB_allocFromBufferOwn that takes ownership of the buffer

Avoids duplicating the image buffer when saving thumbnails.
---
 source/blender/imbuf/IMB_imbuf.h         |  8 ++++++++
 source/blender/imbuf/intern/allocimbuf.c | 35 ++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

(limited to 'source/blender/imbuf')

diff --git a/source/blender/imbuf/IMB_imbuf.h b/source/blender/imbuf/IMB_imbuf.h
index 4ad7aa98484..dd8e6549e24 100644
--- a/source/blender/imbuf/IMB_imbuf.h
+++ b/source/blender/imbuf/IMB_imbuf.h
@@ -148,6 +148,14 @@ struct ImBuf *IMB_allocImBuf(unsigned int x,
 bool IMB_initImBuf(
     struct ImBuf *ibuf, unsigned int x, unsigned int y, unsigned char planes, unsigned int flags);
 
+/**
+ * Create a copy of a pixel buffer and wrap it to a new ImBuf
+ * (transferring ownership to the in imbuf).
+ * \attention Defined in allocimbuf.c
+ */
+struct ImBuf *IMB_allocFromBufferOwn(
+    unsigned int *rect, float *rectf, unsigned int w, unsigned int h, unsigned int channels);
+
 /**
  * Create a copy of a pixel buffer and wrap it to a new ImBuf
  * \attention Defined in allocimbuf.c
diff --git a/source/blender/imbuf/intern/allocimbuf.c b/source/blender/imbuf/intern/allocimbuf.c
index d327981f583..c2bff9ddc51 100644
--- a/source/blender/imbuf/intern/allocimbuf.c
+++ b/source/blender/imbuf/intern/allocimbuf.c
@@ -430,6 +430,41 @@ bool imb_addrectImBuf(ImBuf *ibuf)
   return false;
 }
 
+/**
+ * \param take_ownership: When true, the buffers become owned by the resulting image.
+ */
+struct ImBuf *IMB_allocFromBufferOwn(
+    unsigned int *rect, float *rectf, unsigned int w, unsigned int h, unsigned int channels)
+{
+  ImBuf *ibuf = NULL;
+
+  if (!(rect || rectf)) {
+    return NULL;
+  }
+
+  ibuf = IMB_allocImBuf(w, h, 32, 0);
+
+  ibuf->channels = channels;
+
+  /* Avoid #MEM_dupallocN since the buffers might not be allocated using guarded-allocation. */
+  if (rectf) {
+    BLI_assert(MEM_allocN_len(rectf) == sizeof(float[4]) * w * h);
+    ibuf->rect_float = rectf;
+
+    ibuf->flags |= IB_rectfloat;
+    ibuf->mall |= IB_rectfloat;
+  }
+  if (rect) {
+    BLI_assert(MEM_allocN_len(rect) == sizeof(uchar[4]) * w * h);
+    ibuf->rect = rect;
+
+    ibuf->flags |= IB_rect;
+    ibuf->mall |= IB_rect;
+  }
+
+  return ibuf;
+}
+
 struct ImBuf *IMB_allocFromBuffer(const unsigned int *rect,
                                   const float *rectf,
                                   unsigned int w,
-- 
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