Add list_clip_formats example and CLIP_ENABLE_LIST_FORMATS flag (off …

…by default)

Only available on Windows at the moment.

CMakeLists.txt

@@ -15,6 +15,9 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
 endif()
 
 option(CLIP_ENABLE_IMAGE "Compile with support to copy/paste images" on)
+if(WIN32)
+  option(CLIP_ENABLE_LIST_FORMATS "Compile with support to list clipboard formats" off)
+endif()
 option(CLIP_EXAMPLES "Compile clip examples" on)
 option(CLIP_TESTS "Compile clip tests" on)
 if(UNIX AND NOT APPLE)
@@ -28,6 +31,10 @@ if(CLIP_ENABLE_IMAGE)
   target_compile_definitions(clip PUBLIC -DCLIP_ENABLE_IMAGE=1)
 endif()
 
+if(CLIP_ENABLE_LIST_FORMATS)
+  target_compile_definitions(clip PUBLIC -DCLIP_ENABLE_LIST_FORMATS=1)
+endif()
+
 if(WIN32)
   option(CLIP_SUPPORT_WINXP "Enable Windows XP support" OFF)
 

README.md

@@ -59,6 +59,18 @@ int main() {
   - To be able to copy/paste on Linux you need `libx11-dev`/`libX11-devel` package.
   - To copy/paste images you will need `libpng-dev`/`libpng-devel` package.
 
+## Compilation Flags
+
+* `CLIP_ENABLE_IMAGE`: Enables the support to
+  [copy](examples/put_image.cpp)/[paste](examples/show_image.cpp) images.
+* `CLIP_ENABLE_LIST_FORMATS` (only for Windows): Enables the
+  `clip::lock::list_formats()` API function and the
+  [list_clip_formats](examples/list_clip_formats.cpp) example.
+* `CLIP_EXAMPLES`: Compile [examples](examples/).
+* `CLIP_TESTS`: Compile [tests](tests/).
+* `CLIP_X11_WITH_PNG` (only for Linux/X11): Enables support to
+  copy/paste images using the `libpng` library on Linux.
+
 ## Who is using this library?
 
 [Check the wiki](https://github.com/dacap/clip/wiki#who-is-using-clip)

clip.cpp

@@ -1,5 +1,5 @@
 // Clip Library
-// Copyright (c) 2015-2018 David Capello
+// Copyright (c) 2015-2024 David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -72,6 +72,14 @@ bool lock::get_image_spec(image_spec& spec) const {
 
 #endif // CLIP_ENABLE_IMAGE
 
+#if CLIP_ENABLE_LIST_FORMATS
+
+std::vector<format_info> lock::list_formats() const {
+  return p->list_formats();
+}
+
+#endif // CLIP_ENABLE_LIST_FORMATS
+
 format empty_format() { return 0; }
 format text_format()  { return 1; }
 #if CLIP_ENABLE_IMAGE

clip.h

@@ -11,6 +11,7 @@
 #include <cassert>
 #include <memory>
 #include <string>
+#include <vector>
 
 namespace clip {
 
@@ -21,8 +22,22 @@ namespace clip {
   // Clipboard format identifier.
   typedef size_t format;
 
+#if CLIP_ENABLE_IMAGE
   class image;
   struct image_spec;
+#endif // CLIP_ENABLE_IMAGE
+
+#if CLIP_ENABLE_LIST_FORMATS
+  struct format_info {
+    format id = 0;
+    std::string name;
+    format_info(const format id,
+                const std::string& name)
+      : id(id),
+        name(name) {
+    }
+  };
+#endif // CLIP_ENABLE_LIST_FORMATS
 
   class lock {
   public:
@@ -58,6 +73,12 @@ namespace clip {
     bool get_image_spec(image_spec& spec) const;
 #endif // CLIP_ENABLE_IMAGE
 
+#if CLIP_ENABLE_LIST_FORMATS
+    // Returns the list of available formats (by name) in the
+    // clipboard.
+    std::vector<format_info> list_formats() const;
+#endif // CLIP_ENABLE_LIST_FORMATS
+
   private:
     class impl;
     std::unique_ptr<impl> p;

clip_lock_impl.h

@@ -1,5 +1,5 @@
 // Clip Library
-// Copyright (c) 2015-2018 David Capello
+// Copyright (c) 2015-2024 David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -20,9 +20,16 @@ class lock::impl {
   bool set_data(format f, const char* buf, size_t len);
   bool get_data(format f, char* buf, size_t len) const;
   size_t get_data_length(format f) const;
+
+#if CLIP_ENABLE_IMAGE
   bool set_image(const image& image);
   bool get_image(image& image) const;
   bool get_image_spec(image_spec& spec) const;
+#endif // CLIP_ENABLE_IMAGE
+
+#if CLIP_ENABLE_LIST_FORMATS
+  std::vector<format_info> list_formats() const;
+#endif // CLIP_ENABLE_LIST_FORMATS
 
 private:
   bool m_locked;

clip_win.cpp

@@ -1,5 +1,5 @@
 // Clip Library
-// Copyright (C) 2015-2020  David Capello
+// Copyright (C) 2015-2024  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -284,6 +284,46 @@ size_t lock::impl::get_data_length(format f) const {
   return len;
 }
 
+#if CLIP_ENABLE_LIST_FORMATS
+
+std::vector<format_info> lock::impl::list_formats() const {
+  static const char* standard_formats[CF_MAX] = {
+    "", "CF_TEXT", "CF_BITMAP", "CF_METAFILEPICT",
+    "CF_SYLK", "CF_DIF", "CF_TIFF", "CF_OEMTEXT",
+    "CF_DIB", "CF_PALETTE", "CF_PENDATA", "CF_RIFF",
+    "CF_WAVE", "CF_UNICODETEXT", "CF_ENHMETAFILE", "CF_HDROP",
+    "CF_LOCALE", "CF_DIBV5"
+  };
+
+  std::vector<format_info> formats;
+  std::vector<char> format_name(512);
+
+  formats.reserve(CountClipboardFormats());
+
+  UINT format_id = EnumClipboardFormats(0);
+  while (format_id != 0) {
+    if (format_id >= CF_TEXT && format_id < CF_MAX) {
+      // Standard clipboard format
+      formats.emplace_back(format_id, standard_formats[format_id]);
+    }
+    // Get user-defined format name
+    else {
+      int size = GetClipboardFormatNameA(
+        format_id,
+        format_name.data(),
+        format_name.size());
+
+      formats.emplace_back(format_id, std::string(format_name.data(), size));
+    }
+
+    format_id = EnumClipboardFormats(format_id);
+  }
+
+  return formats;
+}
+
+#endif // CLIP_ENABLE_LIST_FORMATS
+
 #if CLIP_ENABLE_IMAGE
 
 bool lock::impl::set_image(const image& image) {

examples/CMakeLists.txt

@@ -15,3 +15,6 @@ if(CLIP_ENABLE_IMAGE)
   add_example(put_image)
   add_example(show_image)
 endif()
+if(CLIP_ENABLE_LIST_FORMATS)
+  add_example(list_clip_formats)
+endif()

examples/list_clip_formats.cpp

@@ -0,0 +1,12 @@
+// Clip Library
+// Copyright (c) 2024 David Capello
+
+#include "clip.h"
+#include <iostream>
+
+int main() {
+  clip::lock l;
+  for (const clip::format_info& info : l.list_formats()) {
+    std::cout << "- [" << info.id << "] " << info.name << "\n";
+  }
+}