Merge pull request #243 from OpenShot/jonoomph-range-checkpixel

Add new parameter to CheckPixel, for checking "close to" pixel colors

Author: jonoomph

include/Frame.h

@@ -250,7 +250,7 @@ namespace openshot
 		const unsigned char* GetPixels(int row);
 
 		/// Check a specific pixel color value (returns True/False)
-		bool CheckPixel(int row, int col, int red, int green, int blue, int alpha);
+		bool CheckPixel(int row, int col, int red, int green, int blue, int alpha, int threshold);
 
 		/// Get height of image
 		int GetHeight();

src/Frame.cpp

@@ -481,7 +481,7 @@ const unsigned char* Frame::GetPixels(int row)
 }
 
 // Check a specific pixel color value (returns True/False)
-bool Frame::CheckPixel(int row, int col, int red, int green, int blue, int alpha) {
+bool Frame::CheckPixel(int row, int col, int red, int green, int blue, int alpha, int threshold) {
 	int col_pos = col * 4; // Find column array position
 	if (!image || row < 0 || row >= (height - 1) ||
 		col_pos < 0 || col_pos >= (width - 1) ) {
@@ -490,10 +490,10 @@ bool Frame::CheckPixel(int row, int col, int red, int green, int blue, int alpha
 	}
 	// Check pixel color
 	const unsigned char* pixels = GetPixels(row);
-	if (pixels[col_pos + 0] == red &&
-		pixels[col_pos + 1] == green &&
-		pixels[col_pos + 2] == blue &&
-		pixels[col_pos + 3] == alpha) {
+	if (pixels[col_pos + 0] >= (red - threshold) && pixels[col_pos + 0] <= (red + threshold) &&
+		pixels[col_pos + 1] >= (green - threshold) && pixels[col_pos + 1] <= (green + threshold) &&
+		pixels[col_pos + 2] >= (blue - threshold) && pixels[col_pos + 2] <= (blue + threshold) &&
+		pixels[col_pos + 3] >= (alpha - threshold) && pixels[col_pos + 3] <= (alpha + threshold)) {
 		// Pixel color matches successfully
 		return true;
 	} else {

tests/FFmpegReader_Tests.cpp

@@ -101,8 +101,8 @@ TEST(FFmpegReader_Check_Video_File)
 	CHECK_EQUAL(255, (int)pixels[pixel_index + 3]);
 
 	// Check pixel function
-	CHECK_EQUAL(true, f->CheckPixel(10, 112, 21, 191, 0, 255));
-	CHECK_EQUAL(false, f->CheckPixel(10, 112, 0, 0, 0, 0));
+	CHECK_EQUAL(true, f->CheckPixel(10, 112, 21, 191, 0, 255, 5));
+	CHECK_EQUAL(false, f->CheckPixel(10, 112, 0, 0, 0, 0, 5));
 
 	// Get frame 1
 	f = r.GetFrame(2);
@@ -118,8 +118,8 @@ TEST(FFmpegReader_Check_Video_File)
 	CHECK_EQUAL(255, (int)pixels[pixel_index + 3]);
 
 	// Check pixel function
-	CHECK_EQUAL(true, f->CheckPixel(10, 112, 0, 96, 188, 255));
-	CHECK_EQUAL(false, f->CheckPixel(10, 112, 0, 0, 0, 0));
+	CHECK_EQUAL(true, f->CheckPixel(10, 112, 0, 96, 188, 255, 5));
+	CHECK_EQUAL(false, f->CheckPixel(10, 112, 0, 0, 0, 0, 5));
 
 	// Close reader
 	r.Close();