Refactor code and create methods to expose functionality that can be reused to implement drag and drop in Windows

[martincapello]

• Separates BitmapInfo implementation from interface, putting code in cpp file and data + methods definitions in header file. It is also moved inside the win namespace. This was needed to be able to reuse the BitmapInfo struct when implementing DragDataProvider::getImage().
• Moves implementation of write_png_on_stream, write_png, and read_png to cpp file and leaves only definitions on header.
• Creates create_img and create_dibv5 functions which basically contains code copy & pasted from other methods with some slight changes.

Related to: aseprite/laf#83

Note: I've noted that using vscode for comparing differences is better than using the split view on Github, at least for these changes, because it shows a better match between lines of codes on each side.

[martincapello]

I know we don't need this namespace here and we could move create_img to the other namespace block. I just did this because the code comparison is actually easier when this code is here (when using vscode to compare changes). If you don't see the point in having this, I will be happy to move it.

[dacap]

The clip_win_wic.h header file was created to expose the WICPngEncoder and WICPngDecoder1/WICPngDecoder2 functionality (https://learn.microsoft.com/en-us/windows/win32/wic/-wic-about-windows-imaging-codec).

I think we should create other clip_win.h to expose the other required functions, and add clip_win_wic.cpp to move all the functions that are WIC related there. I can make this refactor, but I'll need what functions you will need from the laf side.

[dacap]

I'll check aseprite/laf#83 tomorrow to do this refactor and expose the same set of functions.

[martincapello]

The clip_win_wic.h header file was created to expose the WICPngEncoder and WICPngDecoder1/WICPngDecoder2 functionality (https://learn.microsoft.com/en-us/windows/win32/wic/-wic-about-windows-imaging-codec).

I think we should create other clip_win.h to expose the other required functions, and add clip_win_wic.cpp to move all the functions that are WIC related there. I can make this refactor, but I'll need what functions you will need from the laf side.

Sounds great!

[martincapello]

I'll check aseprite/laf#83 tomorrow to do this refactor and expose the same set of functions.

Okay, let me know if you want me to do the refactor.

[dacap]

I've made the changes in the refactors branch.

The changes in this PR required for laf are introduced in this commit: 4836990 (with some minor changes in the API).

To make aseprite/laf#83 work, you will need these fixes:

diff --git a/os/win/dnd.cpp b/os/win/dnd.cpp
index 001a6a5..b12ce2c 100644
--- a/os/win/dnd.cpp
+++ b/os/win/dnd.cpp
@@ -7,7 +7,9 @@
 #include "os/window.h"
 #include "os/win/dnd.h"
 #include "os/system.h"
-#include "clip/clip_win_wic.h"
+
+#include "clip/clip.h"
+#include "clip/clip_win.h"
 
 #include <shlobj.h>
 
@@ -142,8 +144,8 @@ SurfaceRef DragDataProviderWin::getImage()
   if (m_data->GetData(&fmt, &medium) == S_OK) {
     GLock<BITMAPV5HEADER*> b5(medium.hGlobal);
     clip::win::BitmapInfo bi(b5);
-    if (clip::win::create_img(bi, img)) {
-      bi.fill_spec(spec);
+    if (bi.to_image(img)) {
+      spec = img.spec();
       goto makeSurface;
     }
   }
@@ -152,8 +154,8 @@ SurfaceRef DragDataProviderWin::getImage()
   if (m_data->GetData(&fmt, &medium) == S_OK) {
     GLock<BITMAPINFO*> hbi(medium.hGlobal);
     clip::win::BitmapInfo bi(hbi);
-    if (clip::win::create_img(bi, img)) {
-      bi.fill_spec(spec);
+    if (bi.to_image(img)) {
+      spec = img.spec();
       goto makeSurface;
     }
   }