{"id":2589,"date":"2021-06-10T13:40:41","date_gmt":"2021-06-10T11:40:41","guid":{"rendered":"https:\/\/www.vikingsoftware.com\/uncategorized-da\/qlinear-gradient-strikes-back\/"},"modified":"2021-06-10T13:40:41","modified_gmt":"2021-06-10T11:40:41","slug":"qlinear-gradient-strikes-back","status":"publish","type":"post","link":"https:\/\/www.vikingsoftware.com\/da\/blog-da\/qlinear-gradient-strikes-back\/","title":{"rendered":"QLinearGradient strikes back"},"content":{"rendered":"\t\t
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A long time ago I created a tool to help me in generating the gradient C++ code out of a raster image. Then I lost it, and last year I created it again. To make sure I didn’t lose it again, and in the hopes that other developers don’t have to create it too, I hereby share it with you.  <\/em><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Written by Denis Gofman<\/strong>
2021\/06\/11<\/strong><\/pre>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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What do the images below have in common?<\/span><\/h2>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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\"3pics<\/a><\/div><\/div><\/div><\/figure>
\"3pics<\/a><\/div><\/div><\/div><\/figure>
\"3pics<\/a><\/div><\/div><\/div><\/figure><\/div><\/div>\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Honestly, I hate questions like that, because there are a lot of formally correct answers: They all are rectangular, coded in the same format and shot by the same person (me) in the same location, and so on. But what definitely makes this question annoying is that I obviously, considering the title, want the answer to be: gradients<\/em>.<\/span><\/p>
The analog world around us has almost no clean colors; it is filled by millions of shades in gradients. While the gradient can be interpreted as the \u00abdirection and rate of fastest change\u00bb, the digital world needs a more detailed and digital-related description. One may want to check the Wikipedia for a general definition and all that <\/span>scalar-valued differentiable function F of several variables<\/a><\/strong> stuff, but here I will cover only necessary graphics-related details.<\/span><\/p>
A color gradient (aka color map or a color progression) is a range of position-dependent colors. Usually, it stores colors for some initially known points like \u00abstart\u00bb and \u00abend\u00bb and is used to calculate color values for all other points in-between.<\/span><\/p>
Depending on the sampling step, the calculation for values in the range [<\/span>0.0; 1.0<\/span>] could be a CPU-consuming task. That is one of the reasons why gradients relatively recently appeared in the regular GUI (remember the Windows Vista with its Aero and the first steps of Compiz in Linux).<\/span><\/p>
But there is a scope where gradients have been used for ages as more than just bells and whistles.<\/span><\/p>
\u00a0<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Gradient charts<\/h2>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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