The open source OpenXR runtime
d/ht: make blackbar work with non-square inputs
authored by
Moses Turner
and committed by
Jakob Bornecrantz
ee429ac2
cb7563ec
+44
-7
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src/xrt/drivers/ht/ht_image_math.hpp
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src/xrt/drivers/ht/ht_image_math.hpp
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#include "ht_driver.hpp"
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#include <opencv2/calib3d.hpp>
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#include <opencv2/core/matx.hpp>
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#include <opencv2/imgproc.hpp>
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#include <opencv2/core/types.hpp>
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···
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*/
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static cv::Matx23f
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blackbar(cv::Mat &in, cv::Mat &out, xrt_vec2_i32 out_size)
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blackbar(cv::Mat &in, cv::Mat &out, xrt_size out_size)
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{
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float aspect_ratio_input = in.cols / in.rows;
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float aspect_ratio_output = out_size.x / out_size.y;
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#if 1
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// Easy to think about, always right, but pretty slow:
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// Get a matrix from the original to the scaled down / blackbar'd image, then get one that goes back.
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// Then just warpAffine() it.
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// More expensive on the computer, but cheap in programmer time - I'm somewhat allergic to thinking in pixel
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// coordinates. We can come back and optimize later.
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// Do the black bars need to be on top and bottom, or on left and right?
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float scale_down_w = (float)out_size.w / (float)in.cols; // 128/1280 = 0.1
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float scale_down_h = (float)out_size.h / (float)in.rows; // 128/800 = 0.16
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float scale_down = fmin(scale_down_w, scale_down_h); // 0.1
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float width_inside = (float)in.cols * scale_down;
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float height_inside = (float)in.rows * scale_down;
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float translate_x = (out_size.w - width_inside) / 2; // should be 0 for 1280x800
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float translate_y = (out_size.h - height_inside) / 2; // should be (1280-800)/2 = 240
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cv::Matx23f go;
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// clang-format off
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go(0,0) = scale_down; go(0,1) = 0.0f; go(0,2) = translate_x;
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go(1,0) = 0.0f; go(1,1) = scale_down; go(1,2) = translate_y;
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// clang-format on
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cv::warpAffine(in, out, go, cv::Size(out_size.w, out_size.h));
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cv::Matx23f ret;
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// clang-format off
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ret(0,0) = 1.0f/scale_down; ret(0,1) = 0.0f; ret(0,2) = -translate_x/scale_down;
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ret(1,0) = 0.0f; ret(1,1) = 1.0f/scale_down; ret(1,2) = -translate_y/scale_down;
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// clang-format on
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return ret;
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#else
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// Fast, always wrong if the input isn't square. You'd end up using something like this, plus some
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// copyMakeBorder if you want to optimize.
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if (aspect_ratio_input == aspect_ratio_output) {
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cv::resize(in, out, {out_size.x, out_size.y});
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cv::resize(in, out, {out_size.w, out_size.h});
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cv::Matx23f ret;
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float scale_from_out_to_in = (float)in.cols / (float)out_size.x;
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float scale_from_out_to_in = (float)in.cols / (float)out_size.w;
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// clang-format off
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ret(0,0) = scale_from_out_to_in; ret(0,1) = 0.0f; ret(0,2) = 0.0f;
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ret(1,0) = 0.0f; ret(1,1) = scale_from_out_to_in; ret(1,2) = 0.0f;
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ret(0,0) = scale_from_out_to_in; ret(0,1) = 0.0f; ret(0,2) = 0.0f;
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ret(1,0) = 0.0f; ret(1,1) = scale_from_out_to_in; ret(1,2) = 0.0f;
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// clang-format on
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return ret;
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}
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assert(!"Uh oh! Unimplemented!");
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return {};
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#endif
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}
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/*!