Shows a halftone preview.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@6579 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/print/libprint/HalftoneView.h

@@ -0,0 +1,32 @@
+/*
+ * HalftoneView.h
+ * Copyright 2004 Michael Pfeiffer. All Rights Reserved.
+ */
+
+#ifndef _HALFTONE_VIEW_H
+#define _HALFTONE_VIEW_H
+
+#include <View.h>
+#include "Halftone.h"
+
+class HalftonePreviewView : public BView
+{
+public:
+	HalftonePreviewView(BRect frame, const char* name, uint32 resizeMask, uint32 flags);
+
+	void preview(float gamma, float min, Halftone::DitherType ditherType, bool color);
+};
+
+class HalftoneView : public BView
+{
+public:
+	HalftoneView(BRect frame, const char* name, uint32 resizeMask, uint32 flags);
+
+	void preview(float gamma, float min, Halftone::DitherType ditherType, bool color);
+
+private:
+	HalftonePreviewView* fPreview;
+};
+
+#endif
+

src/add-ons/print/drivers/shared/libprint/HalftoneView.cpp

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+#include "HalftoneView.h"
+
+#include <Bitmap.h>
+#include <StringView.h>
+
+HalftonePreviewView::HalftonePreviewView(
+	BRect frame, 
+	const char* name, 
+	uint32 resizeMask, 
+	uint32 flags)
+	: BView(frame, name, resizeMask, flags)
+{
+}
+
+void HalftonePreviewView::preview(float gamma, float min, Halftone::DitherType ditherType, bool color)
+{
+	const color_space kColorSpace = B_RGB32;
+	const float right = Bounds().Width();
+	const float bottom = Bounds().Height();
+	BRect rect(0, 0, right, bottom);
+	
+	BBitmap testImage(rect, kColorSpace, true);
+	BBitmap preview(rect, kColorSpace);
+	BView view(rect, "", B_FOLLOW_ALL, B_WILL_DRAW);
+	
+	// create test image
+	testImage.Lock();
+	testImage.AddChild(&view);
+	
+	// color bars
+	const int height = Bounds().IntegerHeight()+1;
+	const int width  = Bounds().IntegerWidth()+1;
+	const int delta  = height / 4;
+	const float red_bottom   = delta - 1;
+	const float green_bottom = red_bottom + delta;
+	const float blue_bottom  = green_bottom + delta;
+	const float gray_bottom  = height - 1;
+	
+	for (int x = 0; x <= right; x ++) {
+		uchar value = x * 255 / width;
+		
+		BPoint from(x, 0);
+		BPoint to(x, red_bottom);
+		// red
+		view.SetHighColor(255, value, value);
+		view.StrokeLine(from, to);
+		// green
+		from.y = to.y+1;
+		to.y = green_bottom;
+		view.SetHighColor(value, 255, value);
+		view.StrokeLine(from, to);
+		// blue
+		from.y = to.y+1;
+		to.y = blue_bottom;
+		view.SetHighColor(value, value, 255);
+		view.StrokeLine(from, to);
+		// gray
+		from.y = to.y+1;
+		to.y = gray_bottom;
+		view.SetHighColor(value, value, value);
+		view.StrokeLine(from, to);
+	}
+
+	view.Sync();
+	testImage.RemoveChild(&view);
+	testImage.Unlock();
+	
+	// create preview image 
+	Halftone halftone(kColorSpace, gamma, min, ditherType);
+	halftone.setBlackValue(Halftone::kLowValueMeansBlack);
+
+	const int widthBytes = (width + 7) / 8; // byte boundary
+	uchar buffer[widthBytes];
+	
+	const uchar* src = (uchar*)testImage.Bits();
+	uchar* dstRow = (uchar*)preview.Bits();
+	
+	const int numPlanes = color ? 3 : 1;
+	if (color) {
+		halftone.setPlanes(Halftone::kPlaneRGB1);
+	}
+
+	for (int y = 0; y < height; y ++) {
+		for (int plane = 0; plane < numPlanes;  plane ++) {
+			// halftone the preview image
+			halftone.dither(buffer, src, 0, y, width);
+			
+			// convert the plane(s) to RGB32
+			ColorRGB32Little* dst = (ColorRGB32Little*)dstRow;
+			const uchar* bitmap = buffer;
+			for (int x = 0; x < width; x ++, dst ++) {
+				const int bit = 7 - (x % 8);
+				const bool isSet = (*bitmap & (1 << bit)) != 0;
+				uchar value = isSet ? 255 : 0;
+				
+				if (color) {
+					switch (plane) {
+						case 0: dst->red = value;
+							break;
+						case 1: dst->green = value;
+							break;
+						case 2: dst->blue = value;
+							break;
+					}
+				} else {
+					dst->red = dst->green = dst->blue = value;
+				}
+				
+				if (bit == 0) {
+					bitmap ++;
+				}
+			}
+		}
+		
+		// next row
+		src += testImage.BytesPerRow();
+		dstRow += preview.BytesPerRow();
+	}
+	
+	SetViewBitmap(&preview);
+	Invalidate();
+}
+
+HalftoneView::HalftoneView(
+	BRect frame, 
+	const char* name, 
+	uint32 resizeMask, 
+	uint32 flags)
+	: BView(frame, name, resizeMask, flags)
+{
+	SetViewColor(ui_color(B_PANEL_BACKGROUND_COLOR));
+
+	BRect r(frame);
+	float size, max;
+	
+	r.OffsetTo(0, 0);
+	const int height = r.IntegerHeight()+1;
+	const int delta  = height / 4;
+	const float red_top   = 0;
+	const float green_top = delta;
+	const float blue_top  = green_top + delta;
+	const float gray_top  = r.bottom - delta;
+	
+	const char* kRedLabel   = "Red: ";
+	const char* kGreenLabel = "Green: ";
+	const char* kBlueLabel  = "Blue: ";
+	const char* kGrayLabel  = "Black: ";
+	
+
+	BFont font(be_plain_font);
+	font_height fh;
+	font.GetHeight(&fh);
+
+	max = size = font.StringWidth(kRedLabel);
+	r.Set(0, 0, size, fh.ascent + fh.descent);
+	r.OffsetTo(0, red_top);
+	r.right = r.left + size;
+	AddChild(new BStringView(r, "red", kRedLabel));
+
+	size = font.StringWidth(kGreenLabel);
+	r.Set(0, 0, size, fh.ascent + fh.descent);
+	if (max < size) max = size;
+	r.OffsetTo(0, green_top);
+	r.right = r.left + size;
+	AddChild(new BStringView(r, "green", kGreenLabel));
+
+	size = font.StringWidth(kBlueLabel);
+	r.Set(0, 0, size, fh.ascent + fh.descent);
+	if (max < size) max = size;
+	r.OffsetTo(0, blue_top);
+	r.right = r.left + size;
+	AddChild(new BStringView(r, "blue", kBlueLabel));
+
+	size = font.StringWidth(kGrayLabel);
+	r.Set(0, 0, size, fh.ascent + fh.descent);
+	if (max < size) max = size;
+	r.OffsetTo(0, gray_top);
+	r.right = r.left + size;
+	AddChild(new BStringView(r, "gray", kGrayLabel));
+
+	r = frame;
+	r.OffsetTo(max, 0);
+	r.right -= max;
+	fPreview = new HalftonePreviewView(r, "preview", resizeMask, flags);
+	AddChild(fPreview);
+}
+
+void HalftoneView::preview(float gamma, float min, Halftone::DitherType ditherType, bool color)
+{
+	fPreview->preview(gamma, min, ditherType, color);
+}