Code to grab & downscale the screen content (used for thumbnail creation, part of patch #1163026)

svn-id: r17978

3 files changed, 211 insertions, 1 deletions

diff --git a/common/module.mk b/common/module.mk
index 885264702b..83177bcfee 100644
--- a/common/module.mk
+++ b/common/module.mk
@@ -22,7 +22,8 @@ MODULE_OBJS += \
 	common/scaler/hq3x.o \
 	common/scaler/scale2x.o \
 	common/scaler/scale3x.o \
-	common/scaler/scalebit.o
+	common/scaler/scalebit.o \
+	common/scaler/thumbnail.o
 
 ifdef HAVE_NASM
 MODULE_OBJS += \
diff --git a/common/scaler.h b/common/scaler.h
index 8460760bf6..37f7be99ff 100644
--- a/common/scaler.h
+++ b/common/scaler.h
@@ -23,6 +23,7 @@
 
 #include "common/stdafx.h"
 #include "common/scummsys.h"
+#include "graphics/surface.h"
 
 extern void InitScalers(uint32 BitFormat);
 
@@ -59,5 +60,21 @@ extern void makeRectStretchable(int &x, int &y, int &w, int &h);
 
 extern int stretch200To240(uint8 *buf, uint32 pitch, int width, int height, int srcX, int srcY, int origSrcY);
 
+// creates a 160x100 thumbnail for 320x200 games
+// and 160x120 thumbnail for 320x240 and 640x480 games
+// only 565 mode
+enum {
+	kThumbnailWidth = 160,
+	kThumbnailHeight1 = 100,
+	kThumbnailHeight2 = 120
+};
+extern void createThumbnail(const uint8* src, uint32 srcPitch, uint8* dstPtr, uint32 dstPitch, int width, int height);
+
+/**
+ * creates a thumbnail from the current screen (without overlay)
+ * @param surf	a surface (will always have 16 bpp after this for now)
+ * @return		false if a error occured
+ */
+extern bool createThumbnailFromScreen(Graphics::Surface* surf);
 
 #endif
diff --git a/common/scaler/thumbnail.cpp b/common/scaler/thumbnail.cpp
new file mode 100644
index 0000000000..6bca8e9f4a
--- /dev/null
+++ b/common/scaler/thumbnail.cpp
@@ -0,0 +1,192 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2001  Ludvig Strigeus
+ * Copyright (C) 2001-2005 The ScummVM project
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * $Header$
+ *
+ */
+
+#include "stdafx.h"
+#include "common/scummsys.h"
+#include "common/system.h"
+
+#include "scaler.h"
+#include "scaler/intern.h"
+
+template<int bitFormat>
+uint16 quadBlockInterpolate(const uint8* src, uint32 srcPitch) {
+	uint16 colorx1y1 = *(((const uint16*)src));
+	uint16 colorx2y1 = *(((const uint16*)src) + 1);
+	
+	uint16 colorx1y2 = *(((const uint16*)(src + srcPitch)));
+	uint16 colorx2y2 = *(((const uint16*)(src + srcPitch)) + 1);
+	
+	return Q_INTERPOLATE<bitFormat>(colorx1y1, colorx2y1, colorx1y2, colorx2y2);			
+}
+
+template<int bitFormat>
+void createThumbnail_2(const uint8* src, uint32 srcPitch, uint8* dstPtr, uint32 dstPitch, int width, int height) {
+	assert(width % 2 == 0);
+	assert(height % 2 == 0);
+	for (int y = 0; y < height; y += 2) {
+		for (int x = 0; x < width; x += 2, dstPtr += 2) {
+			*((uint16*)dstPtr) = quadBlockInterpolate<bitFormat>(src + 2 * x, srcPitch);
+		}
+		dstPtr += (dstPitch - 2 * width / 2);
+		src += 2 * srcPitch;
+	}
+}
+
+template<int bitFormat>
+void createThumbnail_4(const uint8* src, uint32 srcPitch, uint8* dstPtr, uint32 dstPitch, int width, int height) {
+	assert(width % 4 == 0);
+	assert(height % 4 == 0);
+	for (int y = 0; y < height; y += 4) {
+		for (int x = 0; x < width; x += 4, dstPtr += 2) {
+			uint16 upleft = quadBlockInterpolate<bitFormat>(src + 2 * x, srcPitch);
+			uint16 upright = quadBlockInterpolate<bitFormat>(src + 2 * (x + 2), srcPitch);
+			uint16 downleft = quadBlockInterpolate<bitFormat>(src + srcPitch * 2 + 2 * x, srcPitch);
+			uint16 downright = quadBlockInterpolate<bitFormat>(src + srcPitch * 2 + 2 * (x + 2), srcPitch);
+
+			*((uint16*)dstPtr) = Q_INTERPOLATE<bitFormat>(upleft, upright, downleft, downright);			
+		}
+		dstPtr += (dstPitch - 2 * width / 4);
+		src += 4 * srcPitch;
+	}
+}
+
+void createThumbnail(const uint8* src, uint32 srcPitch, uint8* dstPtr, uint32 dstPitch, int width, int height) {
+	// only 1/2 and 1/4 downscale supported
+	if (width != 320 && width != 640)
+		return;
+	
+	int downScaleMode = (width == 320) ? 2 : 4;
+	
+	if (downScaleMode == 2) {
+		if (gBitFormat == 565)
+			createThumbnail_2<565>(src, srcPitch, dstPtr, dstPitch, width, height);
+		else if (gBitFormat == 555)
+			createThumbnail_2<555>(src, srcPitch, dstPtr, dstPitch, width, height);
+	} else if (downScaleMode == 4) {
+		if (gBitFormat == 565)
+			createThumbnail_4<565>(src, srcPitch, dstPtr, dstPitch, width, height);
+		else if (gBitFormat == 555)
+			createThumbnail_4<555>(src, srcPitch, dstPtr, dstPitch, width, height);
+	}
+}
+
+
+/**
+ * Copies the current screen contents to a new surface, using RGB565 format.
+ * WARNING: surf->free() must be called by the user to avoid leaking.
+ * 
+ * @param surf		the surfce to store the data in it
+ */
+static bool grabScreen565(Graphics::Surface *surf) {
+	Graphics::Surface screen;
+	if (!g_system->grabRawScreen(&screen))
+		return false;
+	
+	assert(screen.bytesPerPixel == 1 && screen.pixels != 0);
+	
+	byte palette[256 * 4];
+	g_system->grabPalette(&palette[0], 0, 256);
+	
+	surf->create(screen.w, screen.h, 2);
+	
+	for (uint y = 0; y < screen.h; ++y) {
+		for (uint x = 0; x < screen.w; ++x) {
+			byte r, g, b;
+			r = palette[((uint8*)screen.pixels)[y * screen.pitch + x] * 4];
+			g = palette[((uint8*)screen.pixels)[y * screen.pitch + x] * 4 + 1];
+			b = palette[((uint8*)screen.pixels)[y * screen.pitch + x] * 4 + 2];
+			
+			((uint16*)surf->pixels)[y * surf->w + x] = (((r >> 3) & 0x1F) << 11) | (((g >> 2) & 0x3F) << 5) | ((b >> 3) & 0x1F);
+		}
+	}
+	
+	screen.free();
+	return true;
+}
+
+bool createThumbnailFromScreen(Graphics::Surface* surf) {
+	assert(surf);
+	
+	int screenWidth = g_system->getWidth();
+	int screenHeight = g_system->getHeight();
+	
+	Graphics::Surface screen;
+
+	if (!grabScreen565(&screen))
+		return false;
+
+	uint16 width = screenWidth;
+	
+	if (screenWidth < 320) {
+		// Special case to handle MM NES (uses a screen width of 256)
+		width = 320;
+		
+		// center MM NES screen
+		Graphics::Surface newscreen;
+		newscreen.create(width, screen.h, screen.bytesPerPixel);
+		
+		uint8 *dst = (uint8*)newscreen.getBasePtr((320 - screenWidth) / 2, 0);
+		uint8 *src = (uint8*)screen.getBasePtr(0, 0);
+		uint16 height = screen.h;
+		
+		while (height--) {
+			memcpy(dst, src, screen.pitch);
+			dst += newscreen.pitch;
+			src += screen.pitch;
+		}
+		
+		screen.free();
+		screen = newscreen;
+	} else if (screenWidth == 720) {
+		// Special case to handle Hercules mode
+		width = 640;
+		screenHeight = 400;
+		
+		// cut off menu and so on..
+		Graphics::Surface newscreen;
+		newscreen.create(width, 400, screen.bytesPerPixel);
+
+		uint8 *dst = (uint8*)newscreen.getBasePtr(0, (400 - 240) / 2);
+		uint8 *src = (uint8*)screen.getBasePtr(41, 28);
+
+		for (int y = 0; y < 240; ++y) {
+			memcpy(dst, src, 640 * screen.bytesPerPixel);
+			dst += newscreen.pitch;
+			src += screen.pitch;
+		}
+
+		screen.free();
+		screen = newscreen;
+	}
+	
+	uint16 newHeight = !(screenHeight % 240) ? kThumbnailHeight2 : kThumbnailHeight1;
+	
+	int gBitFormatBackUp = gBitFormat;
+	gBitFormat = 565;
+	surf->create(kThumbnailWidth, newHeight, sizeof(uint16));
+	createThumbnail((const uint8*)screen.pixels, width * sizeof(uint16), (uint8*)surf->pixels, surf->pitch, width, screenHeight);	
+	gBitFormat = gBitFormatBackUp;
+	
+	screen.free();
+	
+	return true;
+}