不存在从 "Magick::Color" 到 "MagickCore::Quantum" 的合适转换函数

Question

我已经知道为什么它会在代码方面给出错误。问题是，我今天开始使用库本身，并按照我发现的教程进行操作。

我安装了 "ImageMagick-7.0.9-1-Q16-x64-dll" 版本的库，并试图找到给出该错误的最短代码，即：

#include <Magick++.h>
int main(){
  Magick::Quantum result = Magick::Color("black");
}

鉴于教程（下一个），应该存在一种从 Magick::Color 转换为 Magic::Quantum 的方法

// Example of using an image pixel cache
Image my_image("640x480", "white"); // we'll use the 'my_image' object in this example
my_image.modifyImage(); // Ensure that there is only one reference to
// underlying image; if this is not done, then the
// image pixels *may* remain unmodified. [???]
Pixels my_pixel_cache(my_image); // allocate an image pixel cache associated with my_image
Quantum* pixels; // 'pixels' is a pointer to a Quantum array
// define the view area that will be accessed via the image pixel cache
int start_x = 10, start_y = 20, size_x = 200, size_y = 100;
// return a pointer to the pixels of the defined pixel cache
pixels = my_pixel_cache.get(start_x, start_y, size_x, size_y);
// set the color of the first pixel from the pixel cache to black (x=10, y=20 on my_image)
*pixels = Color("black");
// set to green the pixel 200 from the pixel cache:
// this pixel is located at x=0, y=1 in the pixel cache (x=10, y=21 on my_image)
*(pixels+200) = Color("green");
// now that the operations on my_pixel_cache have been finalized
// ensure that the pixel cache is transferred back to my_image
my_pixel_cache.sync();

在下面的行

中给出错误（不存在从 "Magick::Color" 到 "MagickCore::Quantum" 的合适的转换函数）

*pixels = Color("black");
*(pixels+200) = Color("green");

Answer 1

我认为您混淆了数据类型和结构。 pixels 表示 Quantum 部分的连续列表。

假设我们正在使用 RGB 色彩空间。您需要设置每个颜色部分。

Color black("black");
*(pixels + 0) = black.quantumRed();
*(pixels + 1) = black.quantumGreen();
*(pixels + 2) = black.quantumBlue();

要设置第 200 个像素，您需要将偏移量乘以每像素部分数。

Color green("green");
int offset = 199 * 3; // First pixel starts at 0, and 3 parts (Red, Green, Blue)
*(pixels + offset + 0) = green.quantumRed();
*(pixels + offset + 1) = green.quantumGreen();
*(pixels + offset + 2) = green.quantumBlue();

不存在从 "Magick::Color" 到 "MagickCore::Quantum" 的合适转换函数

no suitable conversion function from "Magick::Color" to "MagickCore::Quantum" exists

c++

imagemagick

magick++