perf(graph): improve image scaling quality (issue lc-soft#39)

include/LCUI/graph.h

@@ -96,12 +96,28 @@ LCUI_BEGIN_HEADER
 	if( (G)->color_type == LCUI_COLOR_TYPE_ARGB ) {				\
 		(G)->argb[(G)->width*(Y)+(X)] = (C);			\
 	} else {								\
-		(G)->bytes[(G)->bytes_per_row*(Y)+(X)*3] = (C).value>>8;	\
+		(G)->bytes[(G)->bytes_per_row*(Y)+(X)*3] = (C).b;	\
+		(G)->bytes[(G)->bytes_per_row*(Y)+(X)*3+1] = (C).g;	\
+		(G)->bytes[(G)->bytes_per_row*(Y)+(X)*3+2] = (C).r;	\
 	}
 
 #define Graph_SetPixelAlpha(G, X, Y, A)\
 (G)->argb[(G)->width*(Y)+(X)].alpha = (A)
 
+#define Graph_GetPixel(G, X, Y, C)					\
+	if( (G)->color_type == LCUI_COLOR_TYPE_ARGB ) {			\
+		(C) = (G)->argb[(G)->width*((Y)%(G)->height)+((X)%(G)->width)];	\
+	} else {							\
+		(C).value =						\
+		(G)->bytes[(G)->bytes_per_row*((Y)%(G)->height)		\
+		+((X)%(G)->width)*(G)->bytes_per_pixel]<<0		\
+		| (G)->bytes[(G)->bytes_per_row*((Y)%(G)->height)	\
+		+((X)%(G)->width)*(G)->bytes_per_pixel+1]<<8		\
+		| (G)->bytes[(G)->bytes_per_row*((Y)%(G)->height)	\
+		+((X)%(G)->width)*(G)->bytes_per_pixel+2]<<16		\
+		| 0xff<<24;						\
+	}
+
 LCUI_API void Graph_PrintInfo(LCUI_Graph *graph);
 
 LCUI_API void Graph_Init(LCUI_Graph *graph);
@@ -165,6 +181,9 @@ LCUI_API int Graph_SetBlueBits(LCUI_Graph *graph, uchar_t *b, size_t size);
 LCUI_API int Graph_Zoom(const LCUI_Graph *graph, LCUI_Graph *buff,
 			LCUI_BOOL keep_scale, int width, int height);
 
+LCUI_API int Graph_ZoomBilinear(const LCUI_Graph *graph, LCUI_Graph *buff,
+			LCUI_BOOL keep_scale, int width, int height);
+
 LCUI_API int Graph_Cut(const LCUI_Graph *graph, LCUI_Rect rect,
 		       LCUI_Graph *buff);
 

src/graph.c

@@ -697,6 +697,13 @@ static int Graph_FillRectARGB(LCUI_Graph *graph, LCUI_Color color,
 	return 0;
 }
 
+static uchar_t Graph_BilinearResamplingCore(uchar_t a, uchar_t b, uchar_t c,
+					    uchar_t d, float dx, float dy)
+{
+	return a * (1 - dx) * (1 - dy) + b * (dx) * (1 - dy) +
+	       c * (dy) * (1 - dx) + d * (dx * dy);
+}
+
 /*-------------------------------- End ARGB --------------------------------*/
 
 int Graph_SetColorType(LCUI_Graph *graph, int color_type)
@@ -1023,6 +1030,90 @@ int Graph_Zoom(const LCUI_Graph *graph, LCUI_Graph *buff, LCUI_BOOL keep_scale,
 	return 0;
 }
 
+int Graph_ZoomBilinear(const LCUI_Graph *graph, LCUI_Graph *buff,
+		       LCUI_BOOL keep_scale, int width, int height)
+{
+	if (graph->color_type != LCUI_COLOR_TYPE_RGB &&
+	    graph->color_type != LCUI_COLOR_TYPE_ARGB) {
+		/* fall back to nearest scaling */
+		LOG("[graph] unable to perform bilinear scaling, "
+		    "fallback...\n");
+		return Graph_Zoom(graph, buff, keep_scale, width, height);
+	}
+	LCUI_Rect rect;
+	LCUI_ARGB a, b, c, d, t_color;
+	int x, y, i, j;
+	float x_diff, y_diff;
+	double scale_x = 0.0, scale_y = 0.0;
+	if (!Graph_IsValid(graph) || (width <= 0 && height <= 0)) {
+		return -1;
+	}
+	/* 获取引用的有效区域，以及指向引用的对象的指针 */
+	Graph_GetValidRect(graph, &rect);
+	graph = Graph_GetQuote(graph);
+	if (width > 0) {
+		scale_x = 1.0 * rect.width / width;
+	}
+	if (height > 0) {
+		scale_y = 1.0 * rect.height / height;
+	}
+	if (width <= 0) {
+		scale_x = scale_y;
+		width = (int)(0.5 + 1.0 * graph->width / scale_x);
+	}
+	if (height <= 0) {
+		scale_y = scale_x;
+		height = (int)(0.5 + 1.0 * graph->height / scale_y);
+	}
+	/* 如果保持宽高比 */
+	if (keep_scale) {
+		if (scale_x < scale_y) {
+			scale_y = scale_x;
+		} else {
+			scale_x = scale_y;
+		}
+	}
+	buff->color_type = graph->color_type;
+	if (Graph_Create(buff, width, height) < 0) {
+		return -2;
+	}
+	for (i = 0; i < height; i++) {
+		for (j = 0; j < width; j++) {
+			/*
+			 * Qmn = (m, n).
+			 * Qxy1 = (x2 - x) / (x2 - x1) * Q11 + (x - x1) / (x2
+			 * - x1) * Q21
+			 * Qxy2 = (x2 - x) / (x2 - x1) * Q12 + (x - x1) / (x2
+			 * - x1) * Q22
+			 * Qxy = (y2 - y) / (y2 - y1) * Qxy1 + (y - y1) / (y2 -
+			 * y1) * Qxy2
+			 */
+			x = (int)(scale_x * j);
+			y = (int)(scale_y * i);
+			x_diff = (scale_x * j) - x;
+			y_diff = (scale_y * i) - y;
+			Graph_GetPixel(graph, x + rect.x + 0, y + rect.y + 0,
+				       a);
+			Graph_GetPixel(graph, x + rect.x + 1, y + rect.y + 0,
+				       b);
+			Graph_GetPixel(graph, x + rect.x + 0, y + rect.y + 1,
+				       c);
+			Graph_GetPixel(graph, x + rect.x + 1, y + rect.y + 1,
+				       d);
+			t_color.b = Graph_BilinearResamplingCore(
+			    a.b, b.b, c.b, d.b, x_diff, y_diff);
+			t_color.g = Graph_BilinearResamplingCore(
+			    a.g, b.g, c.g, d.g, x_diff, y_diff);
+			t_color.r = Graph_BilinearResamplingCore(
+			    a.r, b.r, c.r, d.r, x_diff, y_diff);
+			t_color.a = Graph_BilinearResamplingCore(
+			    a.a, b.a, c.a, d.a, x_diff, y_diff);
+			Graph_SetPixel(buff, j, i, t_color);
+		}
+	}
+	return 0;
+}
+
 int Graph_Cut(const LCUI_Graph *graph, LCUI_Rect rect, LCUI_Graph *buff)
 {
 	if (!Graph_IsValid(graph)) {

test/Makefile.am

@@ -5,7 +5,7 @@ AM_CFLAGS = -I$(top_builddir)/include $(CODE_COVERAGE_CFLAGS)
 noinst_PROGRAMS = helloworld test test_charset test_touch test_char_render \
 test_string_render test_widget_render test_widget_layout test_widget_flex_layout \
 test_widget_inline_block_layout test_scaling_support test_scrollbar \
-test_textview_resize
+test_textview_resize test_image_scaling_bench
 
 ##指定测试程序的源码文件
 helloworld_SOURCES = helloworld.c
@@ -57,4 +57,7 @@ test_textview_resize_SOURCES = test_textview_resize.c
 test_textview_resize_LDADD = $(top_builddir)/src/libLCUI.la
 test_textview_resize_CFLAGS = $(AM_CFLAGS) -D PREVIEW_MODE
 
+test_image_scaling_bench_SOURCES = test_image_scaling_bench.c
+test_image_scaling_bench_LDADD = $(top_builddir)/src/libLCUI.la
+
 @CODE_COVERAGE_RULES@

test/test_image_scaling_bench.c

@@ -0,0 +1,64 @@
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <LCUI_Build.h>
+#include <LCUI/LCUI.h>
+#include <LCUI/timer.h>
+#include <LCUI/display.h>
+#include <LCUI/gui/widget.h>
+#include <LCUI/gui/builder.h>
+#include <LCUI/graph.h>
+#include <LCUI/image.h>
+
+#ifdef LCUI_BUILD_IN_WIN32
+static void LoggerHandler(const char *str)
+{
+	OutputDebugStringA(str);
+}
+
+static void LoggerHandlerW(const wchar_t *str)
+{
+	OutputDebugStringW(str);
+}
+#endif
+
+int main(int argc, char **argv)
+{
+	LCUI_Graph g_src, g_dst;
+	LCUI_Color t_color;
+	int i;
+	int64_t t0, t1, t2;
+	int resx[] = { 480, 960, 1280, 1366, 1920, 2560, 3840 }, resy;
+	char s_res[32], s_t0[32], s_t1[32];
+#ifdef LCUI_BUILD_IN_WIN32
+	Logger_SetHandler(LoggerHandler);
+	Logger_SetHandlerW(LoggerHandlerW);
+#endif
+	Graph_Init(&g_src);
+	g_src.color_type = LCUI_COLOR_TYPE_ARGB;
+	if (Graph_Create(&g_src, 960, 540) < 0) {
+		return -2;
+	}
+	t_color.value = 0xffaa5500;
+	Graph_FillRect(&g_src, t_color, NULL, false);
+	LOG("%-20s%-20s%s\n", "image size\\method", "Graph_Zoom()",
+	    "Graph_ZoomBilinear()");
+	for (i = 0; i < sizeof(resx) / sizeof(int); i++) {
+		resy = resx[i] * 9 / 16;
+		t0 = LCUI_GetTime();
+		Graph_Init(&g_dst);
+		Graph_Zoom(&g_src, &g_dst, false, resx[i], resy);
+		Graph_Free(&g_dst);
+		t1 = LCUI_GetTime();
+		Graph_Init(&g_dst);
+		Graph_ZoomBilinear(&g_src, &g_dst, false, resx[i], resy);
+		Graph_Free(&g_dst);
+		t2 = LCUI_GetTime();
+		sprintf(s_res, "%dx%d", resx[i], resy);
+		sprintf(s_t0, "%ldms", t1 - t0);
+		sprintf(s_t1, "%ldms", t2 - t1);
+		LOG("%-20s%-20s%-20s\n", s_res, s_t0, s_t1);
+	}
+	Graph_Free(&g_src);
+	return 0;
+}