[win] Make BitmapInfo::to_image() and create_dibv5() functions public

These functions might be useful for third-party libraries (like laf, aseprite/laf#83) to implement a drag-and-drop functionality. From: #69 Co-authored-by: Martín Capello <[email protected]>
dacap · Apr 12, 2024 · 4836990 · 4836990
1 parent 86e13a4
commit 4836990
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Showing 3 changed files with 248 additions and 190 deletions.
diff --git a/clip_win.cpp b/clip_win.cpp
@@ -7,7 +7,6 @@
 #include "clip_win.h"
 
 #include "clip.h"
-#include "clip_common.h"
 #include "clip_lock_impl.h"
 
 #include <algorithm>
@@ -275,92 +274,10 @@ bool lock::impl::set_image(const image& image) {
  }
  }
 
- image_spec out_spec = spec;
-
- int palette_colors = 0;
- int padding = 0;
- switch (spec.bits_per_pixel) {
- case 24: padding = (4-((spec.width*3)&3))&3; break;
- case 16: padding = ((4-((spec.width*2)&3))&3)/2; break;
- case 8: padding = (4-(spec.width&3))&3; break;
- }
- out_spec.bytes_per_row += padding;
-
- // Create the BITMAPV5HEADER structure
- Hglobal hmem(
- GlobalAlloc(
- GHND,
- sizeof(BITMAPV5HEADER)
- + palette_colors*sizeof(RGBQUAD)
- + out_spec.bytes_per_row*out_spec.height));
+ Hglobal hmem(clip::win::create_dibv5(image));
  if (!hmem)
  return false;
 
- out_spec.red_mask = 0x00ff0000;
- out_spec.green_mask = 0xff00;
- out_spec.blue_mask = 0xff;
- out_spec.alpha_mask = 0xff000000;
- out_spec.red_shift = 16;
- out_spec.green_shift = 8;
- out_spec.blue_shift = 0;
- out_spec.alpha_shift = 24;
-
- BITMAPV5HEADER* bi = (BITMAPV5HEADER*)GlobalLock(hmem);
- bi->bV5Size = sizeof(BITMAPV5HEADER);
- bi->bV5Width = out_spec.width;
- bi->bV5Height = out_spec.height;
- bi->bV5Planes = 1;
- bi->bV5BitCount = (WORD)out_spec.bits_per_pixel;
- bi->bV5Compression = BI_RGB;
- bi->bV5SizeImage = out_spec.bytes_per_row*spec.height;
- bi->bV5RedMask = out_spec.red_mask;
- bi->bV5GreenMask = out_spec.green_mask;
- bi->bV5BlueMask = out_spec.blue_mask;
- bi->bV5AlphaMask = out_spec.alpha_mask;
- bi->bV5CSType = LCS_WINDOWS_COLOR_SPACE;
- bi->bV5Intent = LCS_GM_GRAPHICS;
- bi->bV5ClrUsed = 0;
-
- switch (spec.bits_per_pixel) {
- case 32: {
- const char* src = image.data();
- char* dst = (((char*)bi)+bi->bV5Size) + (out_spec.height-1)*out_spec.bytes_per_row;
- for (long y=spec.height-1; y>=0; --y) {
- const uint32_t* src_x = (const uint32_t*)src;
- uint32_t* dst_x = (uint32_t*)dst;
-
- for (unsigned long x=0; x<spec.width; ++x, ++src_x, ++dst_x) {
- uint32_t c = *src_x;
- int r = ((c & spec.red_mask ) >> spec.red_shift );
- int g = ((c & spec.green_mask) >> spec.green_shift);
- int b = ((c & spec.blue_mask ) >> spec.blue_shift );
- int a = ((c & spec.alpha_mask) >> spec.alpha_shift);
-
- // Windows requires premultiplied RGBA values
- r = r * a / 255;
- g = g * a / 255;
- b = b * a / 255;
-
- *dst_x =
- (r << out_spec.red_shift ) |
- (g << out_spec.green_shift) |
- (b << out_spec.blue_shift ) |
- (a << out_spec.alpha_shift);
- }
-
- src += spec.bytes_per_row;
- dst -= out_spec.bytes_per_row;
- }
- break;
- }
- default:
- error_handler e = get_error_handler();
- if (e)
- e(ErrorCode::ImageNotSupported);
- return false;
- }
-
- GlobalUnlock(hmem);
  SetClipboardData(CF_DIBV5, hmem);
  return true;
 }
@@ -383,85 +300,7 @@ bool lock::impl::get_image(image& output_img) const {
  }
 
  win::BitmapInfo bi;
- if (!bi.is_valid()) {
- // There is no image at all in the clipboard, no need to report
- // this as an error, just return false.
- return false;
- }
-
- image_spec spec;
- bi.fill_spec(spec);
- image img(spec);
-
- switch (bi.bit_count) {
-
- case 32:
- case 24:
- case 16: {
- const uint8_t* src = nullptr;
-
- if (bi.compression == BI_RGB ||
- bi.compression == BI_BITFIELDS) {
- if (bi.b5)
- src = ((uint8_t*)bi.b5) + bi.b5->bV5Size;
- else
- src = ((uint8_t*)bi.bi) + bi.bi->bmiHeader.biSize;
- if (bi.compression == BI_BITFIELDS)
- src += sizeof(RGBQUAD)*3;
- }
-
- if (src) {
- const int src_bytes_per_row = spec.width*((bi.bit_count+7)/8);
- const int padding = (4-(src_bytes_per_row&3))&3;
-
- for (long y=spec.height-1; y>=0; --y, src+=src_bytes_per_row+padding) {
- char* dst = img.data()+y*spec.bytes_per_row;
- std::copy(src, src+src_bytes_per_row, dst);
- }
- }
-
- // Windows uses premultiplied RGB values, and we use straight
- // alpha. So we have to divide all RGB values by its alpha.
- if (bi.bit_count == 32 && spec.alpha_mask) {
- details::divide_rgb_by_alpha(img);
- }
- break;
- }
-
- case 8: {
- assert(bi.bi);
-
- const int colors = (bi.bi->bmiHeader.biClrUsed > 0 ? bi.bi->bmiHeader.biClrUsed: 256);
- std::vector<uint32_t> palette(colors);
- for (int c=0; c<colors; ++c) {
- palette[c] =
- (bi.bi->bmiColors[c].rgbRed << spec.red_shift) |
- (bi.bi->bmiColors[c].rgbGreen << spec.green_shift) |
- (bi.bi->bmiColors[c].rgbBlue << spec.blue_shift);
- }
-
- const uint8_t* src = (((uint8_t*)bi.bi) + bi.bi->bmiHeader.biSize + sizeof(RGBQUAD)*colors);
- const int padding = (4-(spec.width&3))&3;
-
- for (long y=spec.height-1; y>=0; --y, src+=padding) {
- char* dst = img.data()+y*spec.bytes_per_row;
-
- for (unsigned long x=0; x<spec.width; ++x, ++src, dst+=3) {
- int idx = *src;
- if (idx < 0)
- idx = 0;
- else if (idx >= colors)
- idx = colors-1;
-
- *((uint32_t*)dst) = palette[idx];
- }
- }
- break;
- }
- }
-
- std::swap(output_img, img);
- return true;
+ return bi.to_image(output_img);
 }
 
 bool lock::impl::get_image_spec(image_spec& spec) const {