Fixed transparancy in image slicer and sharp resample function

src/gfx/resample_image.cpp

@@ -193,34 +193,83 @@ void sharp_downsample(const Image& img_in, Image& img_out, int amount) {
 	assert(4 * center_weight - 8 * border_weight > 0);
 	
 	Byte *in = img_in.GetData(), *out = img_out.GetData();
+	Byte *al = nullptr, *outa = nullptr;
+	if (img_in.HasAlpha()) {
+		img_out.InitAlpha();
+		al = img_in.GetAlpha();
+		outa = img_out.GetAlpha();
+	}
 	
 	for (int y = 0 ; y < height ; ++y) {
 		for (int x = 0 ; x < width ; ++x) {
-			for (int c = 0 ; c < 3 ; ++c) { // for each component
-				// Filter using a kernel of the form
-				/*     -1 -1
-				 *  -1  c  c -1
-				 *  -1  c  c -1
-				 *     -1 -1
-				 * But when we are near the edge replicate the edge pixel
-				 */
-				int tot =
-				  center_weight * (in[0] + in[3] + in[line] + in[line+3]) - // center
-				  border_weight * (
-				    (x   == 0      ? in[0]    + in[line]   : in[-3]     + in[line-3])  +  // left
-				    (x+1 == width  ? in[3]    + in[line+3] : in[6]      + in[line+6])  +  // right
-				    (y   == 0      ? in[0]    + in[3]      : in[-line]  + in[3-line])  +  // top
-				    (y+1 == height ? in[line] + in[line+3] : in[line*2] + in[line*2+3]) );// bottom
-				// And then avarage the result into a single pixel (downsample by factor 2)
-				out[0] = col( tot / (4 * center_weight - 8 * border_weight) );
-				// next pixel
-				++in;
-				++out;
+			if (x==150&&y==150) {
+			x=x;//break
+			}
+			// Filter using a kernel of the form
+			/*     -1 -1
+			 *  -1  c  c -1
+			 *  -1  c  c -1
+			 *     -1 -1
+			 * But when we are near the edge ignore the pixel
+			 */
+			// when there is alpha, all weights are multiplied by 4*255
+			int center_alpha = al ? al[0] + al[1] + al[width*2] + al[width*2+1] : 1;
+			int weight = center_weight * center_alpha * 4;
+			int sumR   = center_weight * center_alpha * (in[0] + in[3] + in[line+0] + in[line+3]);
+			int sumG   = center_weight * center_alpha * (in[1] + in[4] + in[line+1] + in[line+4]);
+			int sumB   = center_weight * center_alpha * (in[2] + in[5] + in[line+2] + in[line+5]);
+			// edges
+			if (x != 0) {
+				int a = al ? border_weight * min(2 * (al[-1] + al[width*2-1]), center_alpha)
+				           : border_weight;
+				sumR -= a * (in[-3] + in[line-3]);
+				sumG -= a * (in[-2] + in[line-2]);
+				sumB -= a * (in[-1] + in[line-1]);
+				weight -= a * 2;
+			}
+			if (x+1 != width) {
+				int a = al ? border_weight * min(2 * (al[2] + al[width*2+2]), center_alpha)
+				           : border_weight;
+				sumR -= a * (in[6] + in[line+6]);
+				sumG -= a * (in[7] + in[line+7]);
+				sumB -= a * (in[8] + in[line+8]);
+				weight -= a * 2;
+			}
+			if (y != 0) {
+				int a = al ? border_weight * min(2 * (al[-width*2] + al[-width*2+1]), center_alpha)
+				           : border_weight;
+				sumR -= a * (in[-line+0] + in[-line+3]);
+				sumG -= a * (in[-line+1] + in[-line+4]);
+				sumB -= a * (in[-line+2] + in[-line+5]);
+				weight -= a * 2;
+			}
+			if (y+1 != height) {
+				int a = al ? border_weight * min(2 * (al[width*2*2] + al[width*2*2+1]), center_alpha)
+				           : border_weight;
+				sumR -= a * (in[line*2+0] + in[line*2+3]);
+				sumG -= a * (in[line*2+1] + in[line*2+4]);
+				sumB -= a * (in[line*2+2] + in[line*2+5]);
+				weight -= a * 2;
+			}
+			// And then avarage the result into a single pixel (downsample by factor 2 in both dimensions)
+			if (weight > 0) {
+				out[0] = col( sumR / weight );
+				out[1] = col( sumG / weight );
+				out[2] = col( sumB / weight );
+			} else {
+				out[0] = out[1] = out[2] = 0;
+			}
+			if (al) {
+				outa[0] = center_alpha / 4;
+				outa += 1;
+				al += 2;
 			}
-			// skip a pixel
-			in += 3;
+			// next pixel
+			in  += 6;
+			out += 3;
 		}
 		// skip a line
 		in += line;
+		if (al) al += width*2;
 	}
 }

src/gui/image_slice_window.cpp

@@ -360,6 +360,8 @@ void ImageSlicePreview::draw(DC& dc) {
 		Image image = slice.getSlice();
 		if (mask && mask->size == slice.target_size) {
 			mask->setAlpha(image);
+		}
+		if (image.HasAlpha()) {
 			// create bitmap
 			bitmap = Bitmap(image.GetWidth(), image.GetHeight());
 			wxMemoryDC mdc; mdc.SelectObject(bitmap);
@@ -446,9 +448,22 @@ void ImageSliceSelector::draw(DC& dc) {
 	int width  = int(slice.selection.width  * scaleX);
 	int height = int(slice.selection.height * scaleY);
 	// background
-	dc.SetPen(*wxTRANSPARENT_PEN);
-	dc.SetBrush(Color(128,128,128));
-	dc.DrawRectangle(0, 0, s.GetWidth(), s.GetHeight());
+	{
+		RotatedDC rdc(dc, 0, RealRect(0,0,s.x,s.y), 1, QUALITY_LOW);
+		draw_checker(rdc, RealRect(0,0,s.x,s.y));
+	}
+	// edge
+	{
+		wxRegion r(0,0,s.x,s.y);
+		r.Subtract(wxRect(border,border, s.x-2*border, s.y-2*border));
+		dc.SetClippingRegion(r);
+		dc.SetPen(*wxTRANSPARENT_PEN);
+		dc.SetBrush(Color(191,191,191));
+		dc.SetLogicalFunction(wxAND);
+		dc.DrawRectangle(0, 0, s.x, s.y);
+		dc.SetLogicalFunction(wxCOPY);
+		dc.DestroyClippingRegion();
+	}
 	// bitmap : unselected
 	dc.DrawBitmap(bitmap_no_sel, border, border);
 	// draw selected part ungreyed over it
@@ -536,6 +551,11 @@ void ImageSliceSelector::createBitmap() {
 	blur_image(img_no_sel, img_no_sel);
 	blur_image(img_no_sel, img_no_sel);
 	desaturate_image(img_no_sel);
+	if (img.HasAlpha()) {
+		// copy alpha
+		img_no_sel.InitAlpha();
+		memcpy(img_no_sel.GetAlpha(), img.GetAlpha(), img.GetWidth() * img.GetHeight());
+	}
 	bitmap_no_sel = Bitmap(img_no_sel);
 }
 

src/gui/value/image.cpp

@@ -46,7 +46,8 @@ void ImageValueEditor::sliceImage(const Image& image) {
 	if (s.ShowModal() == wxID_OK) {
 		// store the image into the set
 		FileName new_image_file = getSet().newFileName(field().name,_("")); // a new unique name in the package
-		s.getImage().SaveFile(getSet().nameOut(new_image_file), wxBITMAP_TYPE_JPEG);
+		Image img = s.getImage();
+		img.SaveFile(getSet().nameOut(new_image_file), img.HasAlpha() ? wxBITMAP_TYPE_PNG : wxBITMAP_TYPE_JPEG);
 		getSet().actions.add(value_action(valueP(), new_image_file));
 	}
 }