From fa8e8eeecfdbc16be6a55862af02b39c8b55c492 Mon Sep 17 00:00:00 2001
From: Abou Al Montacir <abou.almontacir@sfr.fr>
Date: Fri, 24 Nov 2023 19:10:17 +0100
Subject: [PATCH] GTK3: Fixed rendering of images using 24 bits per pixel.

Closes: #40374. Thanks To: Anton Kavalenka.

When the image is stored in a buffer using 24 bits per pixel, we don't
need to copy pixel by pixel unless the components order is wrong.
We can use `System.move` in this case.

This is the same thing that is used for 32 bit images.
---
 lcl/interfaces/gtk3/gtk3lclintf.inc | 38 +++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/lcl/interfaces/gtk3/gtk3lclintf.inc b/lcl/interfaces/gtk3/gtk3lclintf.inc
index a116b44f68..e3ba82b7d1 100644
--- a/lcl/interfaces/gtk3/gtk3lclintf.inc
+++ b/lcl/interfaces/gtk3/gtk3lclintf.inc
@@ -230,6 +230,44 @@ begin
 
     GetMem(NewData, ArawImage.DataSize);
 
+    if desc.BitsPerPixel = 1 then
+    begin
+      DbgS('Bit depth not implemented '+inttostr(desc.BitsPerPixel));
+    end
+    else if desc.BitsPerPixel = 8 then
+    begin
+      DbgS('Bit depth not implemented '+inttostr(desc.BitsPerPixel));
+    end
+    else if desc.BitsPerPixel = 16 then
+    begin
+      DbgS('Bit depth not implemented '+inttostr(desc.BitsPerPixel));
+    end
+    else if (desc.BitsPerPixel = 24) and ((Ridx <> 0) or (Gidx <> 1) or (Bidx <> 2) or (AIdx <> 3)) then
+    begin
+      // put components in right order
+      DstRowPtr := NewData;
+      SrcRowPtr := ArawImage.Data;
+      y := Desc.Height;
+      while y > 0 do
+      begin
+        Src := SrcRowPtr;
+        Dst := DstRowPtr;
+        x := Desc.Width;
+        while x > 0 do
+        begin
+          Dst[0] := Src[Ridx];
+          Dst[1] := Src[Gidx];
+          Dst[2] := Src[Bidx];
+
+          Inc(Src, 3);
+          Inc(Dst, 3);
+          Dec(x);
+        end;
+        Inc(SrcRowPtr, ARowstride);
+        Inc(DstRowPtr, ARowstride);
+        Dec(y);
+      end;
+    end else
     if (Ridx <> 0) or (Gidx <> 1) or (Bidx <> 2) or (AIdx <> 3) then
     begin
       // put components in right order