Real ASCII - Contour Shade Filter

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Real ASCII - Contour Shade Filter

2025-12-21

Tool

/

Real ASCII

This filter renders shading around the edges in the given image. Like shade filter, a palette is required. (Might also require more manual finetuning than the shade filter)

📖 Guide: Contour Shade ASCII Art#

1️⃣ cd to src/contour_shade.

2️⃣ Set up a palette. Recommended save directory is resource/palette_files. Check out the palette tutorial.

3️⃣ Execute contour_shade.py. Example:

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python contour_shade.py --image_path ../../resource/imgs/tsunami.jpg --resize_factor 4 --contrast_factor 16 --resize_method bilinear --thresholds_gamma 1.2

Parameters

argument	help
—image_path	The path of the image.
—save_path	The directory where the result image will be saved to.
—resize_method	The image resize method. Check below for available options.
—resize_factor	The resize factor of the new image.
—contrast_factor	The contrast factor based on the original image.
—sigma_s	The value of color smoothing in area.
—sigma_r	The value of color smoothing in edges.
—thresholds_gamma	Controls the shading (gradient) levels. Higher value makes the algorithm emphasis the bright pixels. (Better granularity)
—palette_path	Use a palette.
—max_workers	The maximum number of multithread workers.
—invert_color	If included, invert the color of the result image.
—sigmaX	The standard deviation of GaussianBlur kernel in the horizontal direction.
—ksize	The kernel size of contour function.
—gx	The image gradient in the horizontal edges.
—gy	The image gradient in the vertical edges.
—color_option	The option to color the image. Check below for available options.
—save_ascii	If included, the characters will be saved to a file.
—save_ascii_path	The path to save the characters. Check out the ‘ascii_output’ folder for the results.
—antialiasing	If included, retain anti-aliasing of the characters.
—reference_num	Only used if the palette file is non-fixed width. Takes previous character as reference to replace ‘filler’ characters. A filler is a 1px * the row height empty character used to filling in the gaps that cannot be matched with the given characters in palette.
—max_num_fill_item	Only used if the palette file is non-fixed width. This value is the maximum number of characters used to fill any gap.
—filler_lambda	Only used if the palette file is non-fixed width. Larger lambda indicates more emphasis on the gap filling with palette characters and less emphasis on the similarity between filling choices and the references.
—char_weight_sum_factor	Only used if the palette file is non-fixed width. This factor indicates the importance of character weights when deciding the next character.
—curr_layer_weight_factor	Only used if the palette file is non-fixed width. This factor indicates the importance of a particular layer when deciding the next character. By default, we assume that the gradient image in higher index have more importance.
—offset_mse_factor	Only used if the palette file is non-fixed width. This factor indicates the importance of mean squared error when deciding the next character. Higher MSE means less likely to be chosen.
—coherence_score_factor	Only used if the palette file is non-fixed width. This factor indicates the importance of staying in the same level when deciding the next character.