Method DrawBackground

Src/TacentView.cpp:1872–1983

void Viewer::DrawBackground(float l, float r, float b, float t, float drawW, float drawH)
{
	if (Config::Global.TransparentWorkArea)
		return;

	Config::ProfileData& profile = Config::GetProfileData();
	Config::ProfileData::BackgroundStyleEnum style = profile.GetBackgroundStyle();
	bool overrideBG = CurrImage && CurrImage->OverrideBackgroundColour;
	if (overrideBG)
		style = Config::ProfileData::BackgroundStyleEnum::SolidColour;

	switch (style)
	{
		case Config::ProfileData::BackgroundStyleEnum::None:
			return;

		case Config::ProfileData::BackgroundStyleEnum::Checkerboard:
		{
			// Semitransparent checkerboard background.
			float checkSize = float(profile.BackgroundCheckerboxSize);

			// This is for efficiency. Why draw checrboxes where we don'e have to (off screen)?
			// We cull in widths of 2*checkSize so the alternating checherbox colour works out.
			if (l < 0.0f)
			{
				int numXhidden = int((0.0f-l) / (2.0f*checkSize));
				l += float(numXhidden)*(2.0f*checkSize);
			}
			if (r >= drawW)
			{
				int numXhidden = int((r-drawW) / (2.0f*checkSize));
				r -= float(numXhidden)*(2.0f*checkSize);
			}

			if (b < 0.0f)
			{
				int numYhidden = int((0.0f-b) / (2.0f*checkSize));
				b += float(numYhidden)*(2.0f*checkSize);
			}
			if (t >= drawH)
			{
				int numYhidden = int((t-drawH) / (2.0f*checkSize));
				t -= float(numYhidden)*(2.0f*checkSize);
			}

			int x = 0;
			int y = 0;

			bool lineStartToggle = false;
			float bgH = t - b;
			float bgW = r - l;
			glBegin(GL_QUADS);

			int numCheckQuads = 0;
			while (y*checkSize < bgH)
			{
				bool colourToggle = lineStartToggle;